As far as depth goes, I have been playing Smash Bros since 1999, and I still have yet to feel like I've truly 'mastered' the game. SF IV is arguably deeper, but by the same argument is more limited: all of its various intricacies contribute directly to only one aspect of gameplay: kicking your opponents ass.
Brawl has some depth in that area but, as Khuutra pointed out, broader depth overall simply because of the very wide scope of its many ways of being played. SF IV (admittedly I have only played it somewhat; my brother owns in not me) bores me like 95% of fighters: it starts to feel like you're just memorizing combos after a while. You spend 100 hours mastering the game, then get your ass kicked by some button mashing noobie 3 out of every 20 times; that or you fight somebody who's sunk even MORE of their free time into the game, then they just wipe the floor with you....
Crusty VGchartz old timer who sporadically returns & posts. Let's debate nebulous shit and expand our perpectives. Or whatever.
