Good show, but like you, I watched it online in blocks. Don't think I would have cared to watch it on a week-by-week basis, but we'll see whether I do as season 4 comes out.
Betty's nice on the eyes, but like Changster, I found her a tad underwhelming. I find it hard to sympathize with the whole cookie-cutter middle class emo tragedy, although it is a very real thing (not just in the 60's, but clearly even now). And to me, it is just a form of being emo--the plight of being middle or upper-middle class stuck in surburbia with no real problems but plenty of manufactured ones.
Very interested to see what they do with Don's character in the next seasons. I've come to like Peter, although he's such a douche, haha. Peggy's pretty sly too, and it looks like she's really growing some balls so she'll be a mover and shaker. Everyone's little quirks are what really drive the show.