I use it all the time...works great for me. I even use it live in my Van Halen tribute band as the Oberheim sounds are so authentic, it makes the hair on my arms stand. :)
 
-Danny

FWIW I have not had any issues running ST 2.5. Even with up to 12 separate parts running into it. 
 
But I do find the main view really difficult to see. But I think this is an issue with the VST 2 standard, yes? At least, all my VSTi's seem to suffer the same affliction. I thought I read somewhere that this is fixed with VST 3 standard???

joden
FWIW I have not had any issues running ST 2.5. Even with up to 12 separate parts running into it. 
 
But I do find the main view really difficult to see. But I think this is an issue with the VST 2 standard, yes? At least, all my VSTi's seem to suffer the same affliction. I thought I read somewhere that this is fixed with VST 3 standard???

For those of us who have trouble seeing the tiny, itty, bitty screen, it is helpful to use the Windows Maginfer tool as a workaround.  I have vision trouble [vintage eyes] and the ST2.5 (and most of the IKM synths) cause me trouble because of their tiny fonts and GUI.  A couple of years ago Bitflipper suggested the use of the Windows Magnifer as a way of helping us use ST2.5 while we await the long anticipated ST3.  Using the Windows Magnifer has made using ST2.5 more manageable during the wait.

Yeah cool tip that...another one is to run Windows in lower res while using it...around 1024x768 maybve a couple above that. This also increases the view size too :)
 
Roll on MP3 is all I can say.  :)

I have stopped using SampleTank (or other IK softsynth) lately, as any Sonar project containing it tends to crash when closing the project.  The problem started after I migrated from XP to W7-64, and is not specific to X2a.