Chris Hein is the best I've ever owned. It can take tweaking/warming up, but I like to think it sounds really good.
Of course, I'm not as much of a stickler for realism. I saw how dumb pretending vis were authentic a long while back (dumb only imo, more power to anyone going for that).
Some would argue that achieving intense expressivity in practically any orchestral instrument is a fool's game because the context of the performance has been taken away. Players, especially those who really like your piece (though true pros are consistently more than competent as a necessary rule) will play your music miles better than the folks hired to record a bunch of orchestral samples. That's why, ultimately, if you truly want your music to be played the way you're hearing it you should aim, financially, mentally...holistically, to have it played by live (or recording) players.
We can fool our families and friends (I should say casual music listeners). But imo virtual composers should accept that they're writing for an objective instrument (or set of) whose player(s) were in a context that had nothing to do with your composition.
I think that might be why vis are getting so popular in the area of music-with-radically-attenuated-dynamics. There's a limited range in music like action trailers (not just), dubstep (or should I say Rock and Pop in general, though I happen to love a lot of the latter two), and other genres that vis can represent perfectly. It's when you're looking for something in the order of the first movement of Mahler's 9th that we are, and looks like will continue to be, fucked. For fun/frustration, try it. Even harder: try Beethoven's opus 132, third movement. There's just too much nuance there, a significant portion of which of which is created via the live performance of said piece. It might be the greatest day in virtual instruments if someone can pull off such a mockup...I personally won't lose sleep waiting for it, folks.
Imo just write, write, write, with a big side order of studying up on both music and your vis. Perhaps not worry so much about power legato and how x sounds like shit whenever I do x. I really believe consistent, religious composing will make you better regardless. It pays off so much, at least it has for me.
Just get things to sound the best they can be, and let me tell you if the day comes when your writing is performed by instrumentalists you will be so happy (I was, still am).
Hokay, well that was kind of on topic lol! Sorry for my Wagnerian longwindedness.