If you do get one, a tube change is pretty much mandatory, as they come stock with awful tubes in all the cases I know of. Also, I'd say the amp performs better wth EL34's rather than the standard 5881's it comes stock with, but that's no problem as you can just flick a switch and slam the EL34's in there, no need for re-biasing or what have you. Other than that, they're good solid amps, with a surprising degree of versatility for a single channel amp. There's a Hi and Lo input, plus a toggleable 5th gain stage, which means you can get a variety of tones with the amp even with only one channel. They have plenty of gain, enough for the vast majority of applications. As a loose guideline to the tone, it's rumoured Laney took one of Tony Iommi's modded JCM800's as a basis for the GH100TI, and the GH50/100L were then subsequently created for those who wanted a more versatile amp (the TI has the 5th gain stage permanently engaged, and more gain in general). These amps are pretty much a different beast to a JCM800 however. They have a similar "British" kind of tone, but a more "modern" voicing/amount of gain in comparison. Constructionwise, the amp chassis is solidly built, and there's a mixture of P2P and PCB in the guts of the amp. I believe Malice ( I think it was him anyway...) just bought one. Drucifer used to own one also, but I don't believe I've seen either of them on this new board as of yet. I own the GH100TI for what it's worth.