I bought a PowerStation to use as an attenuator (actually, it's more of a re-amper) on my Dr. Z amps, and it was fantastic. When I got my Kemper Rack, I now use it as my power amp into my monitor (was using a 2x12 with Celestion F200-X12, now a 1x12 with the Celestion) and it's equally fantastic. I cannot detect any color added by the 6L6's ... I'm sure on a spectrum analyzer it would show up compared to a Class D, but for my environments I'd defy anyone to hear the difference. The PowerStation is expensive, but given it's various uses, it's really worth it -- particularly if you even need tube amp attenuation. And its 50w of tube power -- it's LOUD, but can also whisper without losing tone.
With the Thiele 1x12 its makes a nice, portable kit. The PowerStation is in the rack with the Kemper and a power supply (6U rack). I also got a back panel from BTPA that let's me have quick, easy connections out the back of the rack.