I went in on the 4-pack for Borderlands, and it's a blast. The RPG elements aren't as strong as more traditional titles, but the lack of armor customization is pretty much there to keep things moving along faster. We ALREADY spend 5+ minutes sorting through the guns that drop during large encounters. If they had a full armor set like most games, we'd forget how to fight by the time we got done fiddling with it all.
Although I will say right now that I hate the way the cars drive. They drive like the warthogs in Halo, which also are designed to Piss You Right The Fuck Off. You can't look around the vehicle without turning that direction, so we have to rely on callouts from one of the people in the turrets. Before figuring this out, we were running the cars into rock walls (and each other) all the time while just trying to get our bearings.
The absurdly overhyped art style is neat at first but you'll forget all about it after a couple hours.