From the 252 on up, to the 602, on the Paradigm 100's each level up surpassed the former. The 602 sounding the best... IMO.
Personally, I could have lived pretty eaisly with the 402... on the 100's. Primarily due to the expense of the speakers. I'd not likely go with the 500 mono's either, again, due to the relationship of amp cost to speaker cost... BUT... if it's all about sound and there is enough $$$ in the till... with having the speakers already on hand and not wanting to exchange them out again, the 402 or larger Mac amps would definitely be worth checking out.
I preffered the 602 over the 500's, myself on those speakers.. Additionally I liked the large Mc floor standers over the Paradigms too with the MC602 even better. L360's I think.
Having more power on tap is not a bad thing more often than not... so there's that too.
Good luck..