Regardless of how realistic the sounds are, aren't you limited to some degree by having to use a keyboard as a controller. Some playing techniques for other instruments are pretty hard to duplicate with a keyboard. Plus, don't you need to THINK (and phrase) like a seasoned guitarist or sax player or.....what have you. The only decent/authentic solos I've ever heard on 'synths' was when it was imitating other keyboard instruments. JMO, of course.

chas