I bought the Hughes and Kettner after I was disappointed by the Mesa Boogie V Twin. I can say that this unit, while it has less tubes sounds definitely better.
Pros: The clean channel is simply pristine. The half dirty channel has plenty of options, from Clapton-esque to AC/DC sounds. The lead channel is very versatile, especially with the ability to tweak the voicing option. The speaker simulated output is simply great and probably the most realistic that I've heard so far. The EQ is very precise and the switching is fast and noiseless. Build quality is certainly German - very strong, built like a panzer!
1)Support? I wrote email to H&K customer support with some questions about this product - no answer whatsoever so I am not sure how well they'll handle a problem.
2)Only one EQ for all 3 channels which can be limiting in live situations.
3) the lead channel could use a bit more gain for some over the top metal distortion sounds, like for example black metal
4)the brushed aluminum box labelling is hard to see in a stage situation, so are the knobs. It could've been better if H&K thought of some way to use the blue glow lamp on the unit towards providing some illumination where it could actually be useful.
5)Price - it can certainly be prohibitive as some non tube solutions can achieve similar results for half the money.