I admit I like 4th ed. more than the previous editions. And Im completely aware of the MMO party feel, and long combats, but I still like it because each class introduced had a set role to play in the party. It was incredibly easy to teach new players and get them going if they had an idea of what they were to do in battle.
Probably the big thing I liked was all the different variations on healers. You didnt need a cleric. you could use a warlord, a bard, or a shaman instead, and they had their schtick as well for helping the party, be it combat boosts, enemy debuffs or an unkillable minion.