Modelling means it can replicate sounds of multiple amps. It's a meh amp, but if it fits your style and price...
Ya, its like x number of amps in one. I have one, a behringer, and you can get sounds ranging form a calm fender tweed to a crunching lead marshall. Its really an amazing versitile amp and it blows away anything in the pricerange (GMX212) Personally i love it. I dont have 2 carry multiple amps around 4 multiple tones. Plus it has 99 built in effects, 2 channels and can double over as a cab head.