Hello,
I have a Mg 100dfx. Ive had it for a few years or so. Its pretty sick, and wicked loud, ive played in a bunch of gigs with it. The Mg series, in my opinion, is a great bang for your buck. The effects are awesome, at first i didnt care for them but i started fooling around with them and realize they can add a lot of warmth and presence to your sound.
Theres a contour knob on the overdrive channel that can turn your sound from a woody vintage sound to the modern metal style. The distorton is not perfect though.
I say go for the MG its cheap, its loud it, it can sound real sweet if you tweak the knobs right.
...Although once i had to get it reparied for 60 bucks, i dont remember what happened. Something burnt out...it still is a low-end model.