We had seriously thought about re-writing an accounting system using Visual MaxFrame, but eventually decided to buy into AccPac. AccPac has their own class libraries. So, even though we did decide on using Visual MaxFrame and think it is a very excellent product, we eventually took the cheaper route and bought into an accounting package that was already developed.
I think that there are many good products for frameworks, i.e., Mere Mortals, VMP, and Visual ProMatrix beign the three I would focus on.
We really did like Visual MaxFrame and took some classes in it here lcoally for a reasonable cost from Drew Speedie; he isn't called Speedie for no reason at all; he is very speedie when he talks and writes code. You have to work to keep up with him.