Look, the simple answer here is after you install Cakewalk by BandLab, you can still use your existing Sonar exactly as you have been doing.  Since Cakewalk by BandLab will access your existing setup, as well, you have only to gain by the updates they have been releasing.  The only challenge to you is that you have to download the BandLab Assistant app from their site (free).  From there you will download the files and the installation will be automatic.   It doesn't erase or mess up anything you already have.  It sets itself up as another way to access what you already are doing, but better.

Euthymia
I'm going to do my best to be polite.
 
This forum has a search function, and this question has been asked and answered just about weekly for the past 5 months. Use it.
 
And for the past 5 months, the answer has been, and continues to be increasingly so, YES.
 
The exception is the part where the company reveals explicit details about what new features they are planning to add. They may change their policy on that in the future, but you'll need to set aside whatever entitlement you may feel to know what the corporation's plans are.
 
That tends to fall by the wayside with freeware due to the lack of need to rope new licensees in with every release cycle. In its place comes freedom to fix the program where it may be broken.
 
I gladly relinquish the former to gain the latter (along with getting the whole works for free, of course!).

1. First of all, versions change so the answer given months ago may be different today, so I asked.  Also, I haven't BEEN here in many months.
2. The search function here always has been ****e.
3. I don't feel any entitlement whatsoever beyond being able to use the software I bought and paid for in good faith, until such time as it no longer works within Windows.
4.  It's good that Bandlab took over Cakewalk and is even attempting to carry on.  But at the same time I don't need to undertake a massive change to what already works fine to me so again, I ask to get a feel for how people are getting on with this latest version.
 
So forgive me for interrupting the forum so rudely.

CbB started with the unreleased 2017-11 version of Platinum. Since that time the updates have mostly been bug fixes. This month may be different. They have been working on a new feature. We should know in a couple of days. Upgrading to CbB is a pretty low risk operation. What is the worst that could happen? You might have to delete it and perform a clean reinstall of Platinum. Since you just performed a Platinum install so you know what is involved. The clean up before a fresh install only takes a few minutes.

scook
CbB started with the unreleased 2017-11 version of Platinum. Since that time the updates have mostly been bug fixes. This month may be different. They have been working on a new feature. We should know in a couple of days. Upgrading to CbB is a pretty low risk operation. What is the worst that could happen? You might have to delete it and perform a clean reinstall of Platinum. Since you just performed a Platinum install so you know what is involved. The clean up before a fresh install only takes a few minutes.

You make some good points and they are along my lines of thinking as well. Probably get to that this weekend in fact.

I was mostly responding to the "polite" request to use the search function, and why I chose to ask instead.

sorry if it was already mentioned, but you should be aware that it also installs an "assistant" app

I believe this was covered in msgs 4 & 5 above.
 
The "assistant" is not a secret part of the install unless you are referring to something other than BandLab Assistant. If that is the case, I am not sure what the "assistant" is.
 
One must create a BandLab account (use existing Cakewalk account email) and install BandLab Assistant in order to install and activate CbB.
 
IOW, the "it" that installs the "assistant" app is the user.

yes, correct, that's right, you have to install an assistant app before you can install the cbb app

SiberianKhatru59
Probably get to that this weekend in fact.

I was mostly responding to the "polite" request to use the search function, and why I chose to ask instead.

Aw, now I apologized about the search deal before you could even reply, and even followed up with a detailed answer in light of the forum's search being ganked. Install that thing, it's good stuff, and not all just bugfixes, either! It'll make you say Yes!
 
My own biggest frustration: a great new program to explore, but  the forum is locked, so we're populated with people who have been using the program forever and went through the ups and downs and WTF's with the "30th Anniversary/Death/Rumors of our death are exaggerated" announcements.
 
The forum apparently has a useless search function, so approximately 20% of the traffic seems to be either wary people wanting to know if installing BandLab's Cakewalk is going mess up their SONAR installation or dazed people wondering why their support emails for Home Studio are going unanswered.
 
Because everyone who stuck around has been a SONAR user for seemingly decades, the remaining 70% of the traffic is devoted to people trying to straighten out broken configuration issues, with only 10% of the messages posted by people discussing how to use the program, which is inevitably some function I haven't gotten to yet like VocalSync or Drum Replacer.
 
(These numbers are all my personal estimates and are completely made up and are as bull54i7 as the search function, so please, don't beat me up too bad)
 
I'd feel like a total doofus asking something like "how do you make the left-hand side of the piano roll into drum names instead of a piano keyboard?" or "what's this Edit Filter thing they're talking about?" (I know the answers to these questions) Because I think I may literally be the only person on here who had never used SONAR when CbB shipped. I have a Cakewalk ID because I got a free copy of CA/2A a couple of years ago. The Lone N00bie.

SiberianKhatru59
I mean, I'm happy with what I have in all truth, but FREE is, well free after all.  Does Bandlab have a road map posted somewhere to see where they are heading, so I can see if it is worth the (potential) hassle to me before I dive in blindly?

Also, will SPLAT and the CbB versions of SONAR run harmoniously on the same machine?  And if so, will the plug-ins I acquired for use in SONAR (TubeTech channel strip, Rematrix Full and TH3 full, primarily) work within the new CbB version?

No, there is no roadmap yet but you can wait until the next monthly release. This is the first update in which they will include an important new feature and maybe that one worth the switch.

What is the potential downside? I get a new version of CbB on my computer every month and it takes about 10 minutes to download and install the thing.
 
If you do any work in the Piano Roll, there is a Note Duration picker that I would consider handy enough to make it "worth it," even if I didn't consider the increased stability to be enough.