I really like the VH4 cleans. Its tempting to draw comparisons with its sounds, but while its very versatile (clean, crunch, a couple of high gain sounds), it very much has its own flavour for each of those sounds and I suppose you like em or dont. I liked the cleans best, I found the high gain a bit too low mid emphasised and saturated (this from a guy that has a powerball :lol:)
I would LOVE to get my hands on a UL. I adore my CL, its my go-to amp, I can only guess that the UL would be even better for me, given the reputed differences. The sig x is apparently extremely versatile, and more 'normal' sounding than other VHTs (which are very dry, uncompressed and aggressive sounding).
I've seen little but hate for the El Diablo myself, but havent even heard clips, so I shant comment.
By and large very good list, though dave. I'll add:
JVM: I dont consider this ultra-versatile, since its another 'same sound, lots of different EQs and amounts of gain to it' amps. You like that sound or you dont. But its various permutations of that sound go from clean to face melting and does all points in between, and is midi switchable. 4 channels, each with 3 modes, two masters, blah blah; lots of possible permutations. I like mine, I use it often for leads and crunch rhythm. I dont use it so much for higher gain or clean as my other amps do it better to my ears, but it can handle it.
Mesa Mks. All, especially the IV and V. Another really dry breed of amp with lots of versions of and ways to shape a common core sound. Like that dry, articulate, unforgiving voicing and it can do more or less anything for you.
The Invader is indeed very versatile. Had one in here not too long ago, was fun but I prefered my powerball. Its sounds all seemed a little bit engl trying not to be engl; warmer and smoother. Kinda like Marshall TSLs trying to be JCM800s and DRs in the same box. The engl realises this fantasy much better than the TSL did, but I found it lacking the precise laser-guided-pointy-sledgehammer mechanical aggression that I've come to know and love from engls. Maybe that would be a plus to you though :lol:
5150 :lol:
But seriously, if you get a decent amp with more limited options on the front panel, even something single channel, an 800 or deliverance or whatever, and use your guitars volume, a boost/OD and an EQ in the loop, then you can cover massive amounts of territory.