I've read through the threads in the FAQ/Forum and haven't seen one feature that's on MS MCE and ATI 9600 Pro MMC, but not in the forthcoming BM and that's the ability to receive broadcast FM radio signals. Both MCE and MMC 9600Pro allow you "timeshift" the radio broadcast but only MMC allow you to schedule a time to record the broadcast like a PVR. Not having this feature is not a deal breaker but it would be nice to have since BM is pegging itself as the all inclusive media center of the future.
By the way, other companies are trying to get into the timeshifting of radio too besides the ones I've mentioned.
Griffin Technology is one such company but the product has been "coming soon" for the last year and have nothing really to show for it.