Halfway through Series 6, just past "Let's Kill Hitler" to be exact. A few thoughts:
1) The Moffat-era series looks fantastic. "A Christmas Carol" was particualrly gorgeous.
2) I'm a little sad to find that there are fewer single-episode stories in the Eleven era series, particuarly since I know Steven Moffat can write them so well when he wants to. My favourite episodes in Series 5 are "The Beast Below" and "Vincent and the Dcotor" - both stand-alone episodes with little connection to the greater story arc of that series (which was, quite frankly, a bit ridiculous).
3) "Vincent and the Doctor" is a fine example of how Doctor Who, for all that it is a show about a time-travelling hero who fights monsters, is generally awesome in spite of, and not because of the monsters. You know what was interesting about "Vincent and the Doctor"? Pretty much everything except the giant invisible space chicken thing.
4) The weeping angels were scarier the first time around.
5) What I've seen of Series 6 so far, although thin on the stand-alone episodes, does seem to have the most intriguing overall story arc that I've yet seen in Doctor Who. Except for the whole baby thing, which I found a little bit squicky, and which reminded me unpleasantly of the moment Angel started to suck. Seriously, Moffat - you can do better than this.
6) I keep on bouncing between thinking Eleven/River Song is the most awesome thing ever and thinking it was at its best when it happened to Ten. I mean seriously - the story told in Silence in the Library/Forest of the Dead was EPIC in it mystery and tragedy. Finding out the details, while cool in so many obvious ways, is also rife with potential disappointment. (Such as the whole baby thing, which I seriously find a bit creepy. Especially given that the question of whether the Doctor was the father was raised at several points in preceeding episodes. Even though he isn't, considering who the baby turns out to be, I feel dirty for my mind having ever been allowed to go there).
7) Speaking of Forest of the Dead though, the ending of that was a bit cheap too. I mean, it's not actually a happy ending (fake virtual reality world isn't exactly my idea of heaven) but leaves an easy means for the writers to bring River back to life post-library. I love River as a character, but sometimes it's better let a tragedy be a tragedy, IMHO.
8) I seem to have developed an unfortunate taste for doomed romance. Guess which episode got me properly hooked on Doctro Who? It was "The Girl in the Fireplace". And which episode sealed the deal? "Doomsday". Seriously, what is wrong with me?
9) I hope the resolution to Series 6 turns out to be something other than "The Doctor who gets shot is actually a clone while the real Doctor is hiding in human form so the Silence will think he's dead and leave him in peace". Much as I love being right about things, it's kind of boring when what happens is what I predicted happening.
10) Also, what was with the whole "He's been shot twice, so he can't regenerate" business? I'm pretty sure that's not how Time Lords work - and River, at least, ought to know that. Steven Moffat, I trust you to know what you're doing, but seriously. What are you doing to me?
On that note, I must go to bed before I give in to temptation and stay up half the night to finish the series.
Okay, sorry, one more.
11) New Time Lords can be created if humans conceive while flying through the Time Vortex. I don't even want to imagine where the fandom has gone with that one.