I previously had the Paradigm Studio 60's and was bi-amping them with the Marantz MA500's. Sounded great and was a big step up from my Onkyo receiver.
I subsequently sold the monoblocks and bought a used Conrad Johnson MF2250 amp and just bi-wired the 'digms. This was a small jump better than the Marantz Mono's.
So my experience was that a better amp and bi-wiring is preferable to the 4 Marantz monoblocks. Remember the money of an extra set of interconnects( total of 2 pairs needed for 4 mono's) can be added to the money you'd buy a better amp with. The MA500's didn't do any harm to my tweeters in the 3 years they ran and I occasionally cranked it up good.
I subsequently sold the monoblocks and bought a used Conrad Johnson MF2250 amp and just bi-wired the 'digms. This was a small jump better than the Marantz Mono's.
So my experience was that a better amp and bi-wiring is preferable to the 4 Marantz monoblocks. Remember the money of an extra set of interconnects( total of 2 pairs needed for 4 mono's) can be added to the money you'd buy a better amp with. The MA500's didn't do any harm to my tweeters in the 3 years they ran and I occasionally cranked it up good.