I'd say GameFly, but it seems like it'll have one hell of a pre-order bonus.

Welp, seeing how I've only seen very little of it...

I'm very wary to just buy anything sight unseen, so I probably lean towards renting and then buying if it felt "must have." That's actually one of the best features of Gamefly, you don't necessarily have to choose. Unless you're one of those "I need it day one" types. but even then, Gamefly isn't reliable enough to trust.

If you can get it via gamefly why not.  It's not a multiplayer game and I imagine there's not too much replay value.

The involvement of almost the entire Animated Series voice cast and several key comic writers ensures I'm buying this day one. Even if the gameplay lets me down the story and voice acting will make up for it somewhat. And who can seriously pass up the chance to get a 14' battarang?

I'd say buy if you are a Batman fan. Comic writers and the animated series cast on board mean this is a better attempt to get it right than ever before. I was skeptical of the new movies at first also.