Re: 500$ for Fender or Marshall amp
Never tried the MG series but I can say the AVT50 gets plenty loud. I don't really gig these days but I did happen to jam with a friends band a couple weeks ago and I never had to turn up past 4.5 (small outdoor party, PA only for vocals). Plenty loud enough.
Now if I were seriously gigging again I'd move up to a nicer, all tube Marshall (I'm a Marshall fan) but since my playing is mostly at-home jamming and recording I find the AVT to be fine.
I'm not necessarily trying to 'sell you' on the AVT but it is affordable, simple, good onboard gain, and loud as hell if you want it to be, and there's more to it than just high gain metal. It's a good "rock" amp in general.
Again my only real problem with it is the lack of a boost channel when you want to kick out a solo. A friend told me a boost pedal in the FX loop might work but I haven't fooled with it. A boost pedal in-line only serves to compress the signal further, not actually boost your volume.