ha...no offence.
Best bet would be to take a look through the sounds included on the
Soniksynth web site, though I'd bet that it's more heavily weited towards synths than "workstation" instruments, though it has a ton of both.
Can you be more specific in which instruments you'd be looking for? Have you looked at Sampletank2 instead, which is a bit more of an acoustic soundset and less towards the synth side?
What do you use now and what do you like/dislike about it?