I think new they are overpriced. Used though, they can be a bargain find for a multichannel amp.
I bought mine Trace modded, so it has some of the harshness taken out and voicing mods. I really dig the crunch channel most of all. I typicaly don't run my gain past 5 or 6 and I'm able to get harmonic feedback at very low, apt level volumes (which is a Trace/Voodoo feature-sounds equally good at low volumes)
The effects loop and active tone controls are very nice. The Ultra channel can get more 'modern' metal tones.. I won't use any comparisons, as it usually is a matter of ears, taste, personal preference and can start a flame war but it'll get into crossover territory of emulation in voicings of other amps, especially using other tubes, or pedals but I prefer the 6L6's so far in the amp.
It'll take a pedal to the front to smooth out any harshness quite well.
The only weakness is really the clean channel and non active eq on that channel. The mod that Trace did to the clean channel was to take outsome harsh edge, but I find its more of a pain to match volumes to the clean and gain stages much like on a ADA or similar older processors than anything else.