No step sequencer or Pro Channel in PT ?? That's a deal breaker for me. 

When I was getting into music on computers Protools and Cubase were all I'd heard of.
 
I tried the LE Win 98 version of Protools but couldn't get it to work. Probably my crap PC.
 
A friend had Cubase SX3 and I was just about to get it when another friend showed me his Sonar 6.
It was just more intuitive for a new comer  like me than the others. I decided to buy it and it was less than SX3.
 
 
As computers have become more powerful DSP hardware isn't needed so interfaces are cheaper than ever.
 
Protools ruled once because computers were not powerful you needed an interface with DSP power.
Commercial studios needed that reliability and thus Protools the defacto standard.
 
Many heavily invested in Protools systems and defend their expensive purchases to this day and one thing is for sure PT user base are loyal. Even today it has the best youtube tutorial support of all the DAWs.
 
That makes it more accessible to learning it than any other DAW
 
 
 

Learning Sonar isn't hard, there's tons of support and learning tools available. Affording PT's was a problem for me. Their demo's never worked right on my computers and would crash constantly for me. So saving up for a program that would crash so much never made any sense to me. Sonar was my best solution. 

When I jumped from Sonar to Pro Tools I wanted to bang my head against my desk on many of occasions.  I pretty much hated Pro Tools, coming from Sonar.  But after learning it, I think it is an incredible program and worth all the hype....when doing audio editing and post production.
 
For creating music I prefer Sonar by a mile.  I couldn't live without my Sonar synths.  (oh and track templates/effect chains!)
 
Sonar for audio editing and post production would make me want to bang my head against the wall though.
 
Craig had a good post above, he and I disagree on one point, the comping feature in Pro Tools is way faster for me.  I still haven't figured out a good workflow for X3 comping yet.  Also, time stretching in Pro Tools is light years ahead of audio snap.  Actually, audio snap might be the worst thing about Sonar (outside of staff view).
 
I'm rambling lots of points.  To answer your question, there is a fairly large learning curve going to Pro Tools from Sonar.  I enjoy both programs now, but only break out PT11 HD when I am doing post or surround work.

I've got PTHD 9. Is the upgrade to 11 worth it. It's $999 so it's not cheap.

LpMike75
When I jumped from Sonar to Pro Tools I wanted to bang my head against my desk on many of occasions.  I pretty much hated Pro Tools, coming from Sonar.  But after learning it, I think it is an incredible program and worth all the hype....when doing audio editing and post production.
 
For creating music I prefer Sonar by a mile.  I couldn't live without my Sonar synths.  (oh and track templates/effect chains!)
 
Sonar for audio editing and post production would make me want to bang my head against the wall though.
 
Craig had a good post above, he and I disagree on one point, the comping feature in Pro Tools is way faster for me.  I still haven't figured out a good workflow for X3 comping yet.  Also, time stretching in Pro Tools is light years ahead of audio snap.  Actually, audio snap might be the worst thing about Sonar (outside of staff view).
 

Yes, I agree with everything you say here EXCEPT about comping.  The new comping in SonarX3 is brilliant and leaves my clients literally speechless.  You must learn it.  It has changed the way I record (for the better).  
 
Totally agree about stretching in PT vs. Audio snap.

Anderton
My current version is PT 10, so I may have missed some extra goodies in PT 11 but in any event, Pro Tools was always the program I recommended for people who were transitioning from 2" 24-track and a mixer to a computer. It's not a single-window program like Sonar X-series, Live, or Reason; people from the tape world were comfortable going to something with separate mixing and recording windows and an obvious, simple workflow.
 
Pro Tools has maintained that stripped-down, traditional recording paradigm while adding features like warp audio, floating-point audio engine, non-real-time bounce, envelopes that didn't require a separate folder, and Beat Detective, although almost always after these features had appeared in other programs. I'm sure there are features I'm overlooking, but other than Beat Detective I really can't think of anything offhand that Pro Tools innovated since it first appeared. MIDI is improved, although still not on a par with the Cubase/Logic/Sonar trio - the emphasis remains on audio recording and mixing. Including a version of Sibelius for notation is a plus but note that although a lot of people assume it's a full version, it's not. FWIW I think the stretchable content that's included is above average in terms of putting sketches together quickly in various genres.
 
What you won't find at all is pretty much anything relating to dance, beats, or EDM other than warp audio. You can't Acidize files or create Apple Loops, there's nothing like the matrix view, no step sequencer, etc. You can't do something like turn a wav file into a stretchable loop, drag it to the desktop, then drag it back in somewhere else. If I had to do EDM on Pro Tools, I'd probably go insane. Same with comping; X3 really changed the game for DAWs in general with that one. I found punches a lot easier in PT than comping (if the artist was any good).
 
PT's PDC is primitive compared to Sonar and other programs, which has tripped me up more than once with things like the UA plugs. But at least it exists now, and I think the worst of its issues have likely been sorted out.
 
Dave is right about the shortcuts, I suggest investing in one of those Pro Tools-specific QWERTY keyboards. If you don't and get one later, you'll kick yourself for not having bought it sooner.
 
For tracking, editing, and mixing, Pro Tools will do what you need it to do, and do it more or less like everyone else so there's not much of a learning curve. As long as you stay within its proscribed functionality, Pro Tools is a relatively painless experience (assuming a sufficiently powerful computing environment, of course). But if you want to venture even a little bit out of the box, it can be very frustrating. I did a hip-hop session back in October that tracked with Pro Tools but when it came time to mix, I had to bring the tracks into Sonar. I couldn't do what was needed in the PT environment.
 
So why do I use Sonar instead of Pro Tools? I do a huge variety of projects that require an equally huge variety of production techniques. I need to be able to shift from rock, to EDM, to remixes, to a quickie soundtrack, to narration, to restoration, etc. There are even some mastering techniques I've developed that can be done most efficiently in Sonar, and I have not found a program whose workflow is compatible with so many project types. But if my goal was simply to track musicians, edit the tracks, do punches, and mix, Pro Tools would do everything I needed.

Anderton
My current version is PT 10, so I may have missed some extra goodies in PT 11 but in any event, Pro Tools was always the program I recommended for people who were transitioning from 2" 24-track and a mixer to a computer. It's not a single-window program like Sonar X-series, Live, or Reason; people from the tape world were comfortable going to something with separate mixing and recording windows and an obvious, simple workflow.
 
Pro Tools has maintained that stripped-down, traditional recording paradigm while adding features like warp audio, floating-point audio engine, non-real-time bounce, envelopes that didn't require a separate folder, and Beat Detective, although almost always after these features had appeared in other programs. I'm sure there are features I'm overlooking, but other than Beat Detective I really can't think of anything offhand that Pro Tools innovated since it first appeared. MIDI is improved, although still not on a par with the Cubase/Logic/Sonar trio - the emphasis remains on audio recording and mixing. Including a version of Sibelius for notation is a plus but note that although a lot of people assume it's a full version, it's not. FWIW I think the stretchable content that's included is above average in terms of putting sketches together quickly in various genres.
 
What you won't find at all is pretty much anything relating to dance, beats, or EDM other than warp audio. You can't Acidize files or create Apple Loops, there's nothing like the matrix view, no step sequencer, etc. You can't do something like turn a wav file into a stretchable loop, drag it to the desktop, then drag it back in somewhere else. If I had to do EDM on Pro Tools, I'd probably go insane. Same with comping; X3 really changed the game for DAWs in general with that one. I found punches a lot easier in PT than comping (if the artist was any good).
 
PT's PDC is primitive compared to Sonar and other programs, which has tripped me up more than once with things like the UA plugs. But at least it exists now, and I think the worst of its issues have likely been sorted out.
 
Dave is right about the shortcuts, I suggest investing in one of those Pro Tools-specific QWERTY keyboards. If you don't and get one later, you'll kick yourself for not having bought it sooner.
 
For tracking, editing, and mixing, Pro Tools will do what you need it to do, and do it more or less like everyone else so there's not much of a learning curve. As long as you stay within its proscribed functionality, Pro Tools is a relatively painless experience (assuming a sufficiently powerful computing environment, of course). But if you want to venture even a little bit out of the box, it can be very frustrating. I did a hip-hop session back in October that tracked with Pro Tools but when it came time to mix, I had to bring the tracks into Sonar. I couldn't do what was needed in the PT environment.
 
So why do I use Sonar instead of Pro Tools? I do a huge variety of projects that require an equally huge variety of production techniques. I need to be able to shift from rock, to EDM, to remixes, to a quickie soundtrack, to narration, to restoration, etc. There are even some mastering techniques I've developed that can be done most efficiently in Sonar, and I have not found a program whose workflow is compatible with so many project types. But if my goal was simply to track musicians, edit the tracks, do punches, and mix, Pro Tools would do everything I needed.

May i ask you what do you think about ableton live , also on the engine and pdc ?
 
sorry to hijak but Craig point of vue is valuable for me ;)

BlixYZ

LpMike75
When I jumped from Sonar to Pro Tools I wanted to bang my head against my desk on many of occasions.  I pretty much hated Pro Tools, coming from Sonar.  But after learning it, I think it is an incredible program and worth all the hype....when doing audio editing and post production.
 
For creating music I prefer Sonar by a mile.  I couldn't live without my Sonar synths.  (oh and track templates/effect chains!)
 
Sonar for audio editing and post production would make me want to bang my head against the wall though.
 
Craig had a good post above, he and I disagree on one point, the comping feature in Pro Tools is way faster for me.  I still haven't figured out a good workflow for X3 comping yet.  Also, time stretching in Pro Tools is light years ahead of audio snap.  Actually, audio snap might be the worst thing about Sonar (outside of staff view).
 

Yes, I agree with everything you say here EXCEPT about comping.  The new comping in SonarX3 is brilliant and leaves my clients literally speechless.  You must learn it.  It has changed the way I record (for the better).  
 
Totally agree about stretching in PT vs. Audio snap.

I should really take a couple hours and just focus on the new comping feature.  I have no doubt it's a good workflow, just a matter of getting used to it.