I've just begun playing through the Beta (why yes, I AM playing games instead of writing the last essay I need to finish before graduation, why wouldn't I be?), and I'm really loving everything I've seen so far. Graphically, everything is gorgeous. I've enjoyed talking with people, and the silly things they had to say (especially the one trainer who spoke like Yoda!).
Some things I've encountered that made me think, but which are not necessarily bugs. Firstly, I was stuck for quite a bit in Mozilla, because I didn't realize I was supposed to talk with my rival in the pokemon center. I think I would have liked him to be a smidgen more obvious. I was getting quite frustrated that I couldn't figure out what I had missed. The only other thing that stood out to me was the weather. Perhaps its just bad luck on my part, but it seems to rain an awful lot.
As I said earlier though, I really love this hack so far.