you'll be disappointed if you can only play offline, it's a training mode for online
Idunno, I bought it for single-player alone because I was half-expecting the P2P to be as unplayable as Borderlands for me. Single player can still be a blast, but if that's your only option then it's definitely worth renting first.
I assume you then are the one guy that hasnt had horrible lag and experienced the worst ai in history?
I lag horribly in every single online game ever because of my connection, but the lag my end is no worse than a CoD title, and the game is actually playable unlike Borderlands. As for AI, here's a pro-tip: select Versus, rather than Solo or Co-Op. AI actually gets pretty balanced and competitive that way.