I've spent a fair amount of time with both the Proac and the DeCApo. The Proac is a better speaker, (partcularly in the midrange, highs and dynamically) but unfortunately your amp, contrary to what another poster said, will not drive them properly. The Proac is not as nearly efficient as the MM de Capo. You'd have to change your amp to use the better speaker.
I don't know what the Cremona is like, so I can't help you there.
I don't know what the Cremona is like, so I can't help you there.