Personally, I have a love/dislike relationship with it. For one, those who claim to be guerilla artists but suck at what they do, should consider night jobs. Seriously. Practice on cardboard & come back with something worth a shit. Please. Don't sully my streets up with your practice sessions. So, too, are taggers with their 30-second "territorial pissings" at the gas station which do nothing to advance real guerilla art, but politically lump the gangland bad in with the street artists that are good. Well, vice-versa that.
Secondly, you'd think that with all their anonymous public works and their ongoing narrative bent on b/f-ucking the system, that they would duck every chance at public adoration/recognition. But instead, they do masked interviews in Juxtpoz magazine with their guerilla artspeak and schlep their multiples (shoes, tshirts, fluffy toys & dolls) on the marketplace - no different than their bretheren counterparts in galleries. Of course, galleries are definitely NOT the end-all-be-all outlet for fine artwork. It should be in the hands of those who can either afford it or it should be good enough for all to appreciate.
On the other hand, if you've got talent and the streets are the only way you can communicate it, so be it. More power to you. The better we can get graff artists to produce, the better a city's chances will be at giving them a public forum for their wares.
I love most Guerilla Art. But it's the gorilla hacks that spoil the soup. IMHO.
