The posts regarding whether or not one of the factions are more/less mature/immature, casual/elitist, social/ignorant don't really do much good..
There's not a certain type of people choosing a certain type of faction on a certain kind of battlegroup/realm. It is all random and there's black sheep on both sides.
totaly freaking worth it. economy is better and people seem generaly nicer than on ally. they are less caveman like than i thought which was badass. and orgrimmar just beats every city in forever.