I fell out of the series after season 2.
Season 1 was great, because I know a lot of guys with the mentality on Mad Men - dinosaurs that never changed how they think, but cover up / mask what they really want to get by. So, I connected with it pretty immediately.
When Don's story surfaced, I felt very "... meh" about it.
It is great what they did obviously, they have won awards, there is a following, so it is not a crap show by any means. But, it is not for me. I love the time piece aspect of it, but I do not like the Don Draper story itself.