Lacks low end. Even after adding a depth mod, it lacked oomph. Some have had good results tweaking the power supply, though.
FX loop sucks. They recommend rack FX for a reason.
11 tubes (7 12AX7's and 4 5881's). That's a lot of tubes to tweak/replace.
Bottom Line (IMO)
I think it's a great amp for old-school metal. Its lack of low end makes it a poor candidate for detuned stuff. It has tons of gain on tap that isn't buzzy unless you want to dial it in that way.
If you're looking for high gain on a budget, I think it's a great choice. If you're looking for a SLO at a 1/4 the price you'll be disappointed.
I have a T-50 that I really like. It grinds well and takes boost pedals nicely. For what they go for, it seems to be pretty well made inside, or at least it looks easy to service.