The adjustment a thereminist has to make when graduating either from the PAIA Theremax or the B3 is considerable. It's like having to learn to play all over again. The standard Etherwave is more responsive and it's far more difficult to mask little pitch variances. In the long run, it will be good for your ear.
You'll also find you can articulate notes more cleanly, and there are more variations possible using the volume antenna to get any number of "attacks" on notes, from soft and medium attack, to really sharp, biting attack.
The wave form and brightness knobs are really fun to experiment with. I've been able to get timbres that are reminiscent of cello, trombone, violin, tenor sax, flute, and clarinet in addition to the more theremin-specific sounds, plus the human vocal qualities. A fellow thereminist who attended a recent performance asked me why I was traveling around with the standard instead of the Pro and I told him it was because there are sonic qualities I can get on my standard that I've never been able to duplicate on the Pro or any other theremin.
Have fun exploring.
