I began getting the DVDs from Netflix at the end of July when I signed up, and upon finishing season 3 went straight to watching season 4 on my friend's TiVo. The Season Finale last night also marked the end of three solid months of consuming Mad Men like a junkie, and I am in the beginning stages of withdrawal.
Gushy descriptions of the writing, acting, and design can be found anywhere, so I will resist the urge to do the same (although I have done so to my family many a time, & for that, Dad, I am sorry). Instead, I will give you my fourth favorite reason for liking the show, and hopefully you won't judge me too harshly for it: I use it as a little bit of an History lesson.
I'm very dumb, so when I learn about a series of events in school, I usually have to make myself a timeline and a flow chart to figure out how all of the things relate to one another. Mad Men has helped me fill in the arc of what (white, employed) people were possibly thinking and doing all though the beginning of the '60s. Being a largely left-brained visual person, seeing a continuum of what people were wearing through those years has actually helped me make a little more sense of photos in textbooks.
Normally I wouldn't allow myself this sort of thing. In costume research, we are only allowed to draw research from primary sources: I should actually watch 'Bye Bye Birdie,' not the episode where Sal (I MISS HIM) makes a commercial based on it. But for solely mind-organizing purposes, I have chosen to trust the intensive research of Weiner, Christopher Brown, Camille Bratkowski, Katherine Jane Bryant, and the whole rest of the crew (art departments, makeup, hair, pattern cutting... wonderful how many people the arts employ), considering the interviews I have heard about the books they keep to track who is wearing what when.
I know the show hasn't gotten renewed on AMC yet, but I don't see why it shouldn't. However, I have gathered from interviews I've heard with Weiner that he doesn't intend to run the show in to the ground, which I am pleased as spiked punch to hear. Even though I can't get enough, it's nice to let things die when then need to (because even 'Cats' didn't have nine lives). But am I going to go out & buy all of the Season DVDs during the Christmas Sales? You bet.