Some observations on SoundCanvas VA after messing with it a bit

--First off, and perhaps most important it sounds EXACTLY like a real SoundCanvas. Well I should say the SC-55 sounds like a real SC-55, I don't have an SC-88Pro to compare to. However near as I can tell the sounds are 100% dead on the original hardware. Only difference I can see is that near as I can tell it goes up to 22kHz output, whereas the original SCs were 16kHz I think (meaning 32kHz sample rate). At any rate if you want a precise SoundCanvas sound, well it has it. It isn't the garbage that some of their past plugins were, it is the real deal.
 
--Despite the warnings on their page, you can use Sonar to send most of what you want to the plugin. It'll take patch changes no problem. Bank changes don't work using the bank drop down menu, but you can send it on MIDI controller 32 and it'll work fine. You can also just select it in the plugin, of course. It isn't as nicely integrated as it should be, but it works fine particularly with old MIDI files.
 
--It plays about 6dB softer than the TTS-1 synth with normal material near as I can tell. It varies a bit, since they have different ideas on instruments.
 
--It does take an absurdly long time to load for some reason. I have an i7-5960K with 32GB of RAM and an XP941 SSD that it runs off of, and yet it take about 5 seconds for the first instance to load. No idea why, the program is tiny. Subsequent instances load in about a second. Once loaded patch changes are immediate of course and resource usage is totally negligible.
 
--It works fine at 88.2kHz and 96kHz near as I can tell. No distortion or aliasing or anything is evident. I haven't tested it higher.
 
--A very strange one: It has a DC offset on its output, it seems. When the plugin is active, but not playing back anything, it outputs a signal at -90.6dB. When you look at said signal, it is just a solid line at that level. I dunno what it is doing. Doesn't particularly matter to sound quality, since it is low level, but it is very strange.
 
--It does have MT-32 compatibility, but it isn't great. It does have a bank selection for CM-64 LA and PCM sounds, which is the MT-32 set, but it seems to be a PCM emulation, not actual Linear Arithmetic synthesis. So it has the right basic tones, but it doesn't give the same sound that a real MT-32 does.
 
--The UI is ugly since they wanted to emulate the look of actual SoundCanvas hardware. It isn't all that hard to use, but more clunky than it should be in the name of looking "vintage".
 
If you want real old school SC sound, then this is probably one of the cheapest ways to get it. Real SC-55s go for a little less on eBay but SC-88s and 88Pros go for a lot more. Also this seems to emulate the lot of them really accurately. More accurate to an SC-55 than my actual Edirol SD-20 (the SD-20 and SD-80 were the successors to the SC-8820 and SC-8850) that's for sure. STill a load of crap that it's $125 though. It should be $50 or less.

I've got a Roland SC-88 Pro. It prolonged the life of my old Yamaha synth (which supported MIDI but predated GM) for quite a few years. The SC-88 Pro sound quality was really great for the time and is still evident. I keep it around to be able to open my old Cakewalk .wrk files just as they were once created using that module. But of course, it's twenty years old now so one of these days it will no longer light up when the power is switched on.
 
This makes buying a SoundCanvas VA sound intriguing and I actually find the GUI retro in a positive way. I haven't tested the demo yet but it sounds promising that you think the sound is spot on. But I do agree that $125 is way too much, especially with all its shortcomings with regard to Sonar. At $50 or below I would also start considering it.