I bought mine used and had it for 7 months. I used it for practice and gigs with a custom cabinet with a single Eminence Delta15LF-4(Ohms) 600w driver with no issues. It's a good option for the price you pay, especially if you get a nice used one as I did.
As most of the D class amps, it's not very reliable if you push it to the limits very often and for long periods of time, but hey! 350watts even at 60% is a lot of power to make it rumble. I sold it once I got his big brother, the PF800.
Ampeg PF-350 Portaflex