BleepingComputer.com: GFI VS. malwarebytes

Hello all,
I just figured I'd let you guys know about this. I am also a member of the GFI forum because I'm in the process of migrating from eset NOD32 to Vipre antivirus. I saw a topic over there asking if the realtime protection mechanism of MBAM is compatible with Vipre antivirus and Antispyware, and Nick Hallin of their support team says no. Just a little pointer for those wondering. And so, all the hype about AVG not allowing it either is really not as much of a surprise as it seems. Most all AV's do that. They don't want any other realtime scanners but theirs. What I wonder though is, is he just saying that for speed purposes, or is it really an incompatibility? What do those here think? Thanks.