I didn't like it as much as the Abc version Once upon a time. I'll keep it a little longer to see how it develops. It kind of reminds me of Supernatural on the Cw.
Once Upon a Time is an interesting fantasy mystery; Grimm struck me as yet another cop show, this one with growling creatures. I could have kept the timer for a few weeks, but I knew when I was paying very little attention to it that this was not a keeper for me. The story just wasn't compelling. So I decided to save myself the hassle and just delete it now. And Since NBC chose to premiere it where tv shows go to die, I suspect NBC expects to be deleting it as well.
NBC ordered another full season of this show. Looks like they got a HIT! Finally.