It's true that some Class D offerings are better than others. The Rotel may be based on an older design. Some of these older designs had poor results because the frequency response was driven by the impedance curve of the speaker. If the speaker had a flat 8 ohm impedance across the board, it would not matter, but most speakers have impedance all over the place, even dropping down to 2-3 ohms in the bass/midbass area.
The new nCore Class D circuit solves a lot of these problems. Newer designs are also better. The Classe Sigma may be a good design. Another one you can look at is the PS Audio Steller series (M700 monoblock or S300 stereo). The PS Audio use Class A input stage which really improves the richness and liveliness of the audio.
Another good contender for Class D is Nord Acoustics. They have many different Class D amps using either nCore or ICE Class D circuits, up to 8 channels. However, their best amps are the "Nord One UP" or Nord One SE" series. These two series include the special Nord input buffer board which allows you to select one of two different discrete Class A input op amps. (choice between Sparkos Labs or Sonic Imagery op amps, both are excellent). The One UP series actually has a 3 channel model, so you could do your front 3 speakers with just this one amp.
The latest designs of these Class D amps are very clean sounding with absolutely no distortion or coloration. I have heard that sometimes recording engineers like to use them because it shows exactly what is it the mix. However, one thing I do not like about these Class D amps in general is the lack of "air" or high frequency response. The end result is a sound that is so clean that it is almost too clean and lacks that "life" or "zest" that makes it real - Class D is almost artificially clean to my ears. Don't get me wrong, there are a large amount of people who just love their Class D amps, but I would rather have a good Class AB for my own preferences. If you think that the lack of high frequency "air" may bother you, I would suggest to look for a dealer that has a Class D amp offering and see how it sound to you - then compare directly to a good resolution Class AB.