I have noticed this too. It will occasionally just stall, for lack of a better word. The latest build is much better in this regard and I've started using it again after having switched over to FF for a while.
I think it's at least partly an aesthetics issue. Mikhail's stuff looked incredible and was shit inside. The 307a is the exact opposite, in my opinion.
In this case, I think it's basically a Ref 3.5 minus etc. -- although those aren't out yet. They've made some changes to the tweeter, added outrigger stands and doubled the price of the floorstanders.