I found borderlands 2 to be fun at first, but once I got as far as breaking into Handsome Jack's city it started to get a little repetative to me, and Game+ seems like a waste of time since it's exactly the same thing.
I found that the unlimited possibilities for guns really weren't that unlimited with only a few guns being actually good and the rest were pretty much useless when you're going above your level on enemies (meaning they're lvl 20 while you're 17).
Hyperion snipers were pretty good but I never got a chace to find those alien guns which was kindof disapointing. I played Borderlands for a while with friends and that was more fun then single player, but the fact that in multiplayer it's cutthroat when it comes to getting guns kindof started fights and stuff.
Customizing is neat and makes you feel accomplished
I didn't really find any real customization options other then skin and head.