Now that both of these things have been playing for a bit... thoughts? ... Personally I'm hooked on once upon a time. It has a quirky and somewhat good-natured presentation. Lighter and fluffier. I'm also loving the casting of Rumpelstiltskin. Grimm, on the other hand, is much darker and heavier although it also has this weird tongue-in-cheek humor. I've only watched two so far (catching up on S01E03 tonight) but so far there has been a little too much similarity between monsters for me. I'm looking forward to something that isn't a variation-on-a-werewolf. Maybe I'll get it tonight!