Ritter's great. I'm still happy with that casting.
My problems with Jessica Jones are such:
1) The character had a lot of her personality completely stripped from her in the transition from comic to screen, and what was added in return didn't make up for that. In fact, I'm not sure there really was anything added that wasn't already present in the source material in the first place.
2) The show (and this so far has held true for almost every Marvel series) is too long by about 1/3rd. The wheel-spinning that needed to take place to justify the runtime? Didn't justify the runtime.
3) The relationship between Jess and Luke started well, but the development from that point was completely fucking botched. Season 1 ends and I got no sense of any real connection between the two worth holding onto. Luke could never meet Jess again and it wouldn't mean shit, which shouldn't be a possibility I could even consider.
4) While Purple Man was the obvious choice in villain, his implementation got mishandled (and his exit was bullshit), starting with the fact his presence more or less eliminated the possibility of allowing the show to just be a Rockford Files-esque detective show, which would have seriously helped point 1).
So basically, while it did some things very well, and it added some thematic depth previously unexplored to the canon of live-action superhero storytelling, that advance (while admirable and necessary) isn't enough to counter, for me, the fact it kinda fucks up Jessica's character, kinda fucked up Luke's, kinda wasted Kilgrave's and wasted about 5 of the show's 13 hours.