Not switching. Not for another year, anyway, maybe never. 

aah...Think I'll go back to Cool Edit Pro.   Still have the disk and a bunch of cracked Waves plugins...  ;-)

After trying several demos I'm not impressed at all with any one DAW. DP9.5 seems the most fun but the UI is made for older low res screens. If they brought it up to speed it would be great.
 
PT has the most aesthetic UI but it won't run on my system.
 
I have Mixcraft Pro 8, Mixbus 4, & SO3 Prime, but none of them do EVERYTHING Sonar does so they will only compliment it.
 
As long as Sonar works I'll be using it. I'm still learning new tricks & tools from the latest updates.

Not really intending to switch just yet, but preparing for a future switch, and looking for an eventual replacement for Sonar. Currently checking out Digital Performer. Hoping to stick with Sonar for as long as possible though.

I'll be using Sonar for the foreseeable future.
I'm a hobbyist, and there's no reason to change at the moment, for me.

Well - I already made the switch to Cubase 9.0 (Now 9.5), since April this year. There where a few reasons for that.
 
I have used Sonar since I started with Home Studio 6 XL (I was also using Project 5, and even now it still runs on Windows 10), and have gone for the full Prof Sonar version since 8.0. Contrary to a lot of users I liked the step to the "X" series, simply because that interface was more to my likings. I also bought most of the console plugins and instruments. Somewhere in 2015 I opted in for the subscription and have gone to Platinum Pro. I started using Cubase LE (and then Artist) around the same time.
 
For me some alarm signs start ringing when I saw those life time subscriptions. I could not imagine that letting your core costumer base pay a one time fee would be a sustainable model to generate income. Even if you try to sell additional plugins (like FL-Studio does), the user base is too small (compared to FL-Studio) to generate a steady income. All this made me feel uneasy.
 
On top of that (and I must be honest here) as a mostly keyboard player and MIDI user, I realized that Cubase just was simply better in that department than Sonar. I dabbled around with the trial version of Studio One, but their MIDI implementation is simply just not up to par with Cubase.
 
And added to that, the cost of staying updated with Sonar was simply more expensive than Cubase. Even with reduction as long time user the yearly cost of Sonar (€162.60 a year) was more expensive than Cubase (alternating a yearly cost of €60 for .5 updates one year and €100 for .0 updates another year, so €160 for two years in total). The math is simple. Pay €160 for two years of updates of Cubase, or pay even more (162,60) for only one year of updates of Sonar. And so - The jump from Sonar to full time Cubase (well almost - I also use Ableton Live but not that much), was made.
 
And what saddens me most is that Cakewalk (in my perception) had a winner in their hands with Project 5. Take a look at Bitwig, and you can see the striking similarity in interface setup (no not the graphics, but the core idea). Project 5 could have been at the same place (and even farther developed) as Bitwig is now, and given the "new" user base of DAW's this latest years, Project 5 could have done even better than Sonar.  Really a pitty that Cakewalk stopped development.
 
Anyway - I made the jump to full time Cubase, and I must say I am very happy with that choice.

You will have to pry Sonar from my cold, dead hands!! I tried S1 and it just didn't fill the void. It would have been nice working with my Notion 6. I have been using Mixbus off and on but no midi notation!
I bought into the Samplitude X3 deal. I had it back in the day of Pro Audio. 9. I think it will fit the bill very nicely for my needs.
It still isn't Sonar.

I don't think there is a need switch, certainly not for a year or two, but I did go for the samplitude X3 Pro deal as a plan B. So far I like it.

 

35mm
Cubase was my first choice but had issues with the UI in the demo. So I bought Studio One. Then the Magix Samplitude Pro X3 Suite crazy deal came along and I bought that. That has turned out to be great for me, and Studio One has turned out to be a pretty useless waste of money.

 
Can you give us some context with regards to the "useless waste of money" ?   For your workflow, for the features, etc etc ?
 
I am still looking/testing...
 
 

There's no need for me to switch to another DAW as Sonar Platinum is working fine for me.   All of my Virtual instruments work inside of it as well as all of my 3rd party VST plugins.   At this point, I am still satisfied with using Sonar.