4x Rets for PvE: DK or Bear?

[wyofiddler]

I meant to ask: Which tank for leading the team? Bleh....

Focus for this team (when they get to 80 and geared a bit) is heroics only, not pvp.

I know the DK lead is the classic setup for pvp, but I'd like to hear what people think about leading with a bear instead. I hear that swipe is king for chain pulls, and bears bring a little different set of buffs. Are they just another option depending on personal preference, or do they make truely stronger pve tanks for an all melee team? How important are DK skills like death strike for the self healing, and does this outweigh the bear abilities? I've played the DK, but have no experience with druids at high level... so my personal bias is in favor of the DK I'm familiar with. Bears just seem so tough as a tank and simple to play. I'd like to hear opinions from anyone willing to comment, thanks