help from revel enthusiasts please

I have to decide whether the revel gems are a significant improvement over the m20's. In both cases the revel b15 sub will be used. It is a nearfield situation where the room is 20w by 12d with an 8ft ceiling. I have the revel f50s in another room and I really like them, but I do not know whether the gems will provide enough improvement to justify the expense. In both cases the electronics will be bryston and lexicon (theater set up) and there will be extensive music listening. No, I cannot change the electronics as I already own them and the speakers are the key variable. thanks for your input.