well,
I think it depends in which ones are on question,
vst and Dx.
there are softwares "adapters" for both, vst -> to Dx and viceversa.
so u can use anyone in any software. someones can´t be opened in some softwares, but u can open them in other ones.
sound forge can open anyone, I have never been in troubles with it.
cool edit pro 1.2 has some problems to open some vst with the arboreum adapter to make them Dx.
Like most Cakewalk users (I think) I sometimes envied those who were able to use VST-instruments in a native environment. It seems so much easier to just pop up any virtual synth (also since there are so many free of charge). Using the VST-wrapper doesn't seem to work as smooth (or is it general apathy myside that I can't get 'em rolling?).
However I read a nice article on the Cake-site revealing upcoming DX-synths and such. Sounds promising for us cakies!
But which is really beter from a quality ang speed point of view in general? I have all the major programs, and I'm wondering which one to waste my time on.