I'm only asking because I see a bit of frustration over the notation in Sonar not being up to par. So, what purpose does it serve for the DAW?

I prefer notation for sequencing midi instruments. I like to write out the bassline for use as a guide when composing the drum parts. Even though I play bass quite well, it's easier for me to compose drum parts when I can see the bassline notated on screen.
 
I also give session players charts, tabs, or sheet music so they can get their parts down faster. 
 
 
I will often keep midi horns, strings, and other hard to find instruments even after replacing midi guitar, keys, vocal melody with real players. 
 
The PRV is extremely difficult for me to use in most cases. 
 
Rhythmically, I understand notation much better than blobs. In PRV, it's very difficult for me to tell if I am looking at 4 eighth notes or 4 sixteenth notes because they can be the same size depending on the zoom level. In notation view, the actual note widths are all the same, they're just different symbols. Forget about tuplets. I really need the little "3" under the triplets, or worse the dreaded little "5." 
 
In notation view, notes are beamed and rests are displayed. No such luck in PRV.  
 
The grand staff fits on my screen nicely which keeps me from having to scroll up and down or zoom in/out to get to the notes I want. 
 
If I am writing a part in the key of E minor, notation view will automatically enter an F# if I click on a line or space that represents F. PRV - Not so much. 
 
I can enter a piece of music into staff view about 5 times faster than I can in PRV. 
 
I will use PRV for drum parts, but only with durations turned off. I am seriously considering using the step-sequencer for writing most drum parts.
 
 

It is a MIDI editing tool for musicians that can read notation.
 

I use it heavily, don't use PRV at all. As John said, if you read music, it's a great editing tool. not so great for printing out as formal notation. The posts you see have been addressing some of the flaws, such as tuplet notation. I have also wished that it could print only the instruments currently playing, like a real score, so that you don't have a bunch of instruments with nothing but rests for pages and pages. Wastes a lot of paper. As Cakewalk does tout it as a notation system you can print from, this should be addressed. Otherwise it's a case of false advertising.

I don't have a strong preference, some projects beg for the PRV, some beg for standard notation, depends on how I am working. And as I type that I realize that in fact I do have a small preference for standard notation - if I need to think about how something gets put together, "seeing" counterpoint, or "seeing" harmonic possibilities.

I suspect that if I put in as much effort to learn to read the PRV it might work for me, but I'm old, I'm grumpy, and frankly I am happy reading standard notation<G>!

Anyway, I don't have a problem with Sonar's staff view - I use it when it works for a given task, and I switch to Finale when I need a full blown editor for standard notation.

I've used the standard notation feature in Cubase, Logic, and DP. They are all a little more capable than Sonar, but none are as capable as Finale (or Sibelius.) So what's the point? I'd rather Cakewalk focus on the sequencer features that are NOT part of Finale - and then maybe extend the MusicXML capabilities.

I  do not need another standard notation tool that does everything - I have Finale for that. So I guess I don't completely understand the frustration, but from a different perspective<G>!


 

Very well put Bill

 Interesting that I use Sonar's staff view is when I need to look at the notation on an imported midi file.  You can separate the notes between 2 staffs.  My notation programs don't do that. I don't always know what the notes are when they are on 12 ledger lines.
 I get tired of people who can't read the dots who claim you don't need notation. If you are trained in theory it's a time saver. It's also a learning tools when you ears don't work as well as your eyes.
 Programs that have traditionally never had notation like Reason and Live, you are seeing users wanting it. The downside is usually adding notation drives up the price of a DAW. 
 

PRV is OK if you're working on one track of midi. But if you are trying to work several tracks at the same time you can't beat having the staff view because the you can fit a lot more info into a smaller space, see a clear delineation between instruments and if you're trained to read notation it's easier. To me chords that are made from the notes are more easily discernible. If something has an unwanted dissonance I think you can spot it faster in the staff view.
What I like the PRV for is changing note durations. It's much easier to do that in PRV, with the one drawback at least for me that the fine control of note length is a little hard to judge sometimes.

Bottom line for me is that they both have their usefulness.  

wst3
I  do not need another standard notation tool that does everything - I have Finale for that. So I guess I don't completely understand the frustration, but from a different perspective<G>!
 

Some of us don't have Finale or Sibelius so it would be nice to have the notation fixed in Sonar .

I write all my music and I was trained to use notes and staves for music just like writers use letters and words to write books.
 
The notation view is certainly not the only way to compose music, but it is the most logical for me.  I do 90% of my creating and arranging in the notation view.
 
If I were only writing a string quartet, for example, I could see possibly using Finale and then importing the music, but I use notation for everything, keyboards, bass, guitars, orchestra and eve drums.