I have the 550exr5 and my sentiments mirror yours. I've got mine powering the full range VMPS RM40's, which are tricky speakes for a single amp, as they require something very smooth, neutral, and resolving for the mids/highs (due to their extremely revealing nature and blinding speed), but also something with iron fisted control and power in the bass (due to their difficult dual woofer bass load and 26 hz extension). The 550exr does both with ease. In fact, after owning if for quite some time now, I've gotten off the upgrade and component switching merry-go-round I was on before. I think this will be my last amp for quite a while still.