I would tend to agree with Maggieowner's very astute descriptions. I would also add that the B&K's and Adcom's tend to get "jumbled up" or "loose control" when pushed hard. Never railed on a Rotel, so don't know about that aspect. I do think that the Rotel probably has the best build quality of the three mentioned though. I also haven't listened to the Anthem, so can't help you on that one either. I would not doubt that it is a pretty solid amp though.
Depending on your personal tastes and the other components in your system, i would keep in mind that the Paradigm's can lean towards sounding bright and / or possibly even glaring if fed a "typical" digital signal. That is, if they make use of a metal dome like many of their models do. In that respect, the B&K may be the best / most forgiving match. Sean