Bit late in the conversation, but I have owned an AH400smx with a 4x10 (8 ohm) since 2001. I only played pub gigs and one larger venue but the tone was awesome. Definitely loud enough. Serviced it myself a couple of times (mainly hoovering out the dust) and its never let me down. Heavy beast. The built in compression is 2nd to none.. I keep the low and high turned up about 3 quarters, just allowing a little attack for the occasional thrash. 2 years ago i added a 1x15 (8 ohm) - oh my god what a difference, the joint 4 ohm allows the full potential of the amp but so wish i had done that years early... Holy hell it is heavy but definitely worth it. The effects loop it top notch too allowing the come and go of silly pedal with its own blend volume.
The T.E sounds (switchable) are also really good, giving true TE warmth if and when you need it. The 12band EQ is also really good too... (remember to clip the low hz)... Mix it all around with the TE sounds and blend of tube and you'll find your sound.
Back in 2001 I paid £800 for the amp & 4x10 with the 1x15 an extra £90 (stupid bargain)... Best £890 i have spent... Countless gigs (and the tone you can achieve with the 2 cabs) this baby has, and will continue to be, my workhorse.