1. That's a bit more difficult to say, they are certainly brighter, more forward/detailed than our HB-1 Mk2's. They are smooth though.
Just to serve as my personal opinion and observation, I wouldn't really characterize them as bright, certainly not overly bright. They don't fatigue my ears after long periods of listening, but each person is different. When we were showcasing the speakers at various audio shows, we didn't really get comments saying that it was bright. We actually got a couple of people who walked in and asked where are the highs. Certainly there are a lot of other speakers I've heard that sounded significantly brighter.
2. Are you talking about the constant directivity design of the horn? If so, then I wouldn't worry about that too much. If anything the horn provides a more controlled off axis response so that it remains smooth and musical off axis. Do you have a diagram of your room layout?