heh, I'm actually watching all the shows mentioned in the OP and the comments.
Grimm is my favorite so far, especially now that the greater story is starting to unfold. Agents of shield is a bit of a "meh", a bit too cheesy for my taste, but still enjoyable enough to watch, mainly because it's in the same universe as Thor.
Out of Arrow and Tomorrow people I like Arrow the most so far, Initially I only watched Arrow for the flashbacks, but it has gotten a lot more interesting lately. Tomorrow people has a really nice story, but dont like the actors or their acting a lot. (seriously the whole tomorrowpeople crew looks like a bunch of pushovers, my grandma could probably beat the crap out of all of them at the same time. :s )
Never gave Once upon a time a chance, mainly because the cover and description of the first episode made it look like it's one of those lady-sci-fi shows, where drama/romance come first and sci-fi/story second, but since you guys posted it alongside these other shows i'll give it a try.
My opinion on Dr Who is a bit extreme, imho Dr Who should be hung from a tree, shot, gutted and run over by a Buick.
Some ongoing or recently finished shows that fit this list you guys might not know of,
-revolution (crappy acting, but really nice story)
Looking forward to a show called 100s which should start in January.