as a modelling unit, there're always tradeoffs.
the obvious pros: huge array of sounds, very versatile especially with the Line 6 controller floorboard, you can (and should, for minimal coloring) go direct to the mixer (as in guitar > POD > mixer), sounds great on recordings and is very convenient.
cons: not a tube amp. the modelling is hit or miss, some are pretty accurate models of amps, some aren't. generally the basic sounds are ok but require tweaking to get them to sound REAL good. effects tend to be hit or miss; most of the modulation effects aren't very good. live at higher volumes it sounds very different from when you play through headphones or on recordings. like all digital modelling amps, it's prone to power spikes, which can wipe out your settings and all your tweaking. make sure you use it with a surge protector.
so...if versatility is your brother's thing, this is a good piece of equipment to get, and you can get great usable sounds if you tweak it for long enough. if you're REALLY particular about sound and you don't mind spending more to get just one sound that you really dig, perhaps a tube amp with a good clean is the place to start. if that's the case, i'd recommend a Fender Blues Junior for pristine clean, a Bassman 50 or 100 (depending on the amount headroom you want) for a warm clean, or Peavey's greatest secret, the Classic 30 or 50 (depending again on how much headroom and volume you require) for a flat clean. very good for building effects on and creating your own sound.