I currently use a pair of 545's to drive the rear ESl's and rear sub woofer in my system. Those same 545's have at times driven my front ESL's. IMO the 545/5400 series are the sweet spot in the Adcom lineup. Sure the 555/5500 and 585 mono's have more power but to me they lose a little of the delicacy and sweetness of the 54 models. I've never tried the 535/5300 series they are a bit underpowered for me.

I should mention the 545/5400 models seem to push more Watt's than their ratings would suggest. This is true for all Adcom power amps.

TBH, I never been as impressed by their tuner preamps. This also applies to their preamps except the 585.