Yep. Going from the Lowell Bair abridgement to Robin Buss' unabridged is a natural step up. I have them both (as well as several other versions).

If you read them side by side, you will notice that there is a greater level of detail in Buss. For example, when Albert shows his paintings to the Count in Paris on his first visit, Buss details exactly what the paintings looked like and what the subjects were and who painted them. Bair simply says that Albert showed the Count his paintings and that they were modern works and the Count knew something about them already.

Not everybody wants that level of detail, so Bair is always a comfortable fall-back if Buss gets to be too much.

Both editions are excellent, very modern and have a lot to offer to their different audiences.