I have a Terror Bass 500 horror story I'm afraid, bought one 2-3 years ago, fairly soon after they first came out. Worked great during that whole time until...
Set up in practice room as normal, the moment I switched it on there was a loud bang, and half of the lights went out*.
Turns out the FET had had enough and shorted, literally blowing up the fuse on the power input and taking a lot of the internal components with it. Currently in the process of getting it fixed but it's requiring a lot of time and a lot of new parts.
The guy fixing it for me has a hatred of class D power sections for this reason- manufacturers use the FETs they would in an all-valve amp but they are subjected to far, far higher electrical frequencies than they can handle.
A look at the Orange forums show many had the same problem, some of them the very first time they used the amp. It's possible this only affected older models though.
If I can get it fixed I'll still use my TB as I absolutely love the sound and portability, but I'll never quite trust it again.
*to clarify, I mean half of the lights in the [i]entire building - [/i]it tripped the circuit breaker for the whole practice space, which means it was sucking an insane amount of current.