Hey Dave,
I'm planning to go to the IB2i when funds allow. The MB2 is just too big for my needs.
Jaxwired, at first I thought the MB2 would overwhelm my room, then I talked to Bryston (the distributor here at the time) and was told that they work well in small rooms. It may be that the size of your room might not be the limiting factor for you. In any case, this line of PMCs are all based on its pro models which are often used in smaller rooms; sometimes, I believe, as near field speakers.
There's no question that MB2s are pricey, but since I've upgraded from the IB2s, and then upgraded from the MB2s to the MB2is, I certainly have no regrets. While I never say never about future upgrades, given how these speakers sound with my 7BSST Squared amps, I have a hard time seeing myself looking for different speakers for my main system.
On the other hand, I've been breaking in Axiom M80s V3 used in my second system, and I'm very impressed so far listening to them driven by an inexpensive Harmon Kardon receiver. I plan the ultimate test: hooking them up to the Bryston amps. Of course, if the M80s, at a small fraction of the price of the MB2is, sound as good as my big PMCs, I'll have to do myself an injury.
Dave