Class "D" has been used for years in the PA systems for sound reinforcement and the companies that produce that equipment have a lot of experience. The designs have been refined and, frankly, the good stuff is at least as good or better than the stuff sold to "consumers." No longer should pro quality PA amps be considered the poor cousin to consumer equipment.
Personally, I use a pro Yamaha PA class "D" amp (around 1000 watts per channel) to drive my electrostats. It sounds great, is ultra reliable and even looks good. I has a built-in limiter and all kinds of speaker and amp protection. Pro equipment like this is designed to be ultra-reliable. I've used many kinds of different amps in the past - both pro and consumer (I'm a lucky guy since I have access to many) and the Yamaha has been my favorite now for several years.
There are lots of choices that sound great as well made by Peavey, Crown and others. The newest Peavy IPR2 amps, for example, are incredibly light and powerful. The IPR2-7500 cranks out over 2000 real RMS Watts both channels driven into four Ohms and weighs in at around 15 pounds. Just be sure to use a 20 Amp ac line to power it.
Just my two cents.