[whpalmer4]

Do you have some reason to think that they failed to consider this option? It is hardly an unprecedented concept :)

My experience on the Mac with complex programs like OmniGraffle has been that it is more difficult to get a good feel for the program's strengths and weaknesses with the 20 items or fewer trials. It is inconvenient that the App Store doesn't provide for limited duration, fully functional trial editions, but given the choice of a limited functionality trial version for an expensive app or no trial, but a 30 day MBG, I would feel safer with the latter approach. The 30% refund penalty gives them extra incentive to provide useful marketing materials, pursue arrangements for having it available on demo units at the Apple Store, etc.