I've got the trial version; it seems much better at handling K10D raw files than anything else I've tried (without using two programs, or a $750 program). It is no slower, but no faster, than the XI I've been using.

I like the gray look, but it's not a deciding factor.

Generally (and for my purposes), X2 is a much better program than XI.

I agree Charlie. I like the new Express Lab and the auto preserve. Have you tried the thinify? It's very clever. You could have some fun!