I've owned one for over 10 years and have gigged with it extensively. The only issue I've ever had with it is the clip light at higher volumes. I play through two cabs (1x15 and 2x10) at 4 ohm, getting the full 500 watts worth of power. I feel as though I'm pushing the limits of it and it will die on me (though it never has). The environments I play in are mostly clubs and outdoor events, with very LOUD drummers. So everyone has to adjust to that volume. I sometimes feel as though I need another 300-500 watts of headroom just so I'm not putting so much of a burden on it. It once rumbled right off the top of my speaker cab and onto the floor. Still worked!
Aside from the clipping issue, its a great little beast. The tone is really good through my Jazz bass...smooth and rich with a good bottom and crisp highs. It comes with these funky feet posts that screw on/off. I use a foam pad without the feet to keep it from vibrating off my cabinet. It has been a steady and reliable workhorse for me for many years.