All of these items are true. The bottom line is that the card is designed with drivers that do not pull the full potential for speed out, but push more for production level design.
That being said, I have a quadro 4 xgl 550, and to be honest. It works quite well with games. I use MOHAA, Some FPS, DIABLOW 2, etc etc and they all work just fine. Somtimes though, in the FPS it may drop to 25-35 FPS as compared to 60+. Not a problem in my book.
If you are not sure which you would pursue, you should get a quadro 4, only because you can do both really. . .who cares about 100+ FPS
just my 2 cents,
-Steve