Following quite a bit of online research, and after a day of trying-out a range of mainly Marshall and Blackstar amps at Andertons, I chose this amp as it was head and shoulders above the rest, including the new YJM100.
Having got the 6L6 home I'm now seriously impressed - it's got guts, especially when warmed-up. The tone controls work really well, so my Pearly Gates loaded Les Paul sounds totally excellent, the Nailbomb loaded BFG is also very good (just back-off the mids a little), the EMG loaded Zakk Wylde sounds a little thin without totally changing all of the settings, and the Tremonti loaded PRS tuned to Eb is absolutely searing - totally blown away by it - and the most biting chords ever!
Key thing for me is that the individual notes remain defined and don't get muddy, even within heavily distorted power or open chords
I reckon that the clean channel is quite fender twin, the crunch/super-crunch channel quite marshall jcm800/900 and the OD channels quite mesa-boogie dual rectifier. I have the ISF on the clean/crunch set slightly towards the british voicing, and the OD set slightly US, the DPR set to 50W and both the resonance and presence set to just over half to really bring forward sound from the 1960A 4x12 cab.
A very flexible amp. Hope this helps!
R