I ran one in my car for about a year, and have one in my boat right now. Pretty solid amps. I think the ratings on the 431 are inflated just a bit, but still a lot of power for the cost. Someone posted bench test numbers on the 430 a couple years back and got it at 296x2. So I would say 100x4 or so is about what you can expect. I never had any reliability issues.
i have a vibe 248 and to this day am surprised at how solid of an amp it is for being so cheap. ive had it for about 3 years now and used to run various subs and never had any problem with it.