It was on sale so I broke down and bought it. I just finished playing the first episode, and while it really nails the visual and audio flair of the movies I can't help but feel that it really didn't "grab" me that much.
I'm willing to chalk it up to initial version shock for now. What I mean by "version shock" is that feeling you get when you are so used to seeing characters portrayed by certain actors, and the vibe of the thing being a certain way, that when you are presented with something that is supposed to be "the same"... but isn't... your mind kind of rejects it at first. And it will take repeated exposure to acclimate to the new version. I had the same thing with the Telltale Batman game... it was just different -enough- that it tweaked the version shock in my brain, and it took a good three episodes before I became invested in the presentation. I think Guardians will be the same.
But I do have to admit that Telltale really did go all out on the musical cues and the look of the game. I think this is the best looking game they've ever made, they really updated their engine. The Batman game looked pretty good, but it still had that kind of clunky hand drawn effect going on that they use on most of their games. I think it was a wise choice to ditch that for Guardians and go with the more CGI character approach they took. It feels like it fits with the thematic presentation of the movies, being this big neon play-doh and chrome galaxy.
Edit: I think I should also mention the in-game animation feels very smooth in Guardians compared to some of the more recent Telltale games, which all felt very stiff and "video gamey". Guardians animations all looked and played very smooth, like watching a CGI television show (how the game SHOULD be) as opposed to looking like you playing some clunky video in Gary's Mod.