Is there a significant difference in power/volume? My drummer and guitarist are fairly loud, but not unreasonable. I would only need to rely on the amp in the practice room, on stage it would always be DI'd to the PA. I know the 800c has a lot more bells and whistles (EQ bands etc.), but I don't really need them. My only worry is that I might have to push the 500 too hard without comfortable headroom...? Cab is the 4 Ohm version btw.