There's no easy answer to this, and I think there's probably no way around an extensive research.

I myself would never like to work in any other software than Cubase, when it comes to virtual instruments and sample libraries. The main reasons are:

• expression maps - I'm a "one track per instrument/section" guy and therefor, these are almost indispensable when using libraries with many patches and articulations, like VSL.
• disable tracks - a fantastic and super-intuitive way of saving machine ressources and employing large project templates on a single machine, without slave PCs, etc.
• probably the best MIDI editor

By the way - Cubase has a quite attractive crossgrade offer.
https://www.steinberg.net/en/landing_pages/cubase_9/competitive_crossgrade.html

I would definitely go with Cubase, mainly for the reasons other users already explained. Other than Cubase, if you mainly work as composer for media, I would take a look to the unique features of Digital Performer.

I really really like Reaper! Its Ultra Flexible and the users can create tools if the software dont come with what you need! The Forum of Reaper is very communicative too and the support are always making new versions, and you can have the trial for ever! ( the reaper it's not a free software, so if you earn some money with it you have to buy, but they dont force you they just belive in your ethic, and I find that beautiful! hahahah )
Try Reaper ! 

I work with Samplitude Pro X3. I like very much the sound of Samplitude, and for editing wave files I like it very much. And I can work well with the midi in it also. But the midi seems to be a bit different from other DAWs and I don't know that other DAWs. I have to say, that I'm a content user of it.

Jimmie there's really no hurry to jump ship just yet.

I have Sonar Platinum and we'll have about two to four years before the OS evolution will render the software "unstable" with constant Windows updates.  Bare in mind that most of those updates are Internet patches anyway and unless you're upgrading to Windows 11 or 12 or 20 Gazillion Pie R Squared the software should still work regardless.  Also, there's always ways to make older software run on modern systems as that is becoming a must for OS developers.

Or, if you're like me and you keep your machine offline,  it will last for as long as your machine will last with current software.  Gibson said that they are still maintaining the Cakewalk servers so if you do get another machine you can still download the last version of Sonar you had.  They are just not creating any new products. 

The question is....  will Gibson at least keep the software up to date with OS evolution?

And there's always the chance that somebody could buy Cakewalk and keep it all going.

Jasen has a good point. Even though they are stopping development, that doesn't mean you have to stop using it right away. Did you update it every month when they were doing those? If not, then this won't really effect you for at least two years unless the VSTs you use or the OS you use change drastically. 

As for which other DAW to pick, I myself prefer FL Studio for making all genres of music. But I have also been using it for 12+ years, so I have kind of a bias. If FL Studio ceased to exist though, I would probably use Cubase and that crossgrade offer is looking quite nice. So if you have to switch, I'd go there as it's the closest thing to SONAR and it plays VERY NICELY with VSTs. (In FL, you have to manually asign most of the CCs).

@LAJ said:

Cubase is the choice of many VSL-users.

@jasensmith said:

there's really no hurry to jump ship just yet.

Well, well, well,  looky here:

https://www.musicradar.com/news/bandlab-rescues-cakewalk-from-gibson

It looks like Sonar and all of Cakewalk is being resurected?

That's similar to what happened with Sony Vegas video - it was picked up by Magix and is now better!    

Well... the guy had Cubase Pro 9.5 in the signature LOL 😛

So what?