First - wow! I really like this series. There are so many good things here - but this isn't a proper review, just a list of a few things that struck me.
The epic backstory, I now see, was Homura's - and epic it truly was. Oddly, the idea of choosing to relive the same period of time over and over in order to save the life of someone you love was something I'd seen just a few months ago in Steins;Gate, in which Okabe does something similar for Mayuri; but that took nothing from its power. (I notice that becoming more kick-ass seems to be an opthalmic remedy, too - Homura loses the need for glasses at some point on the road to becoming the cool girl we meet in Episode 1, much as Indiana Jones does in his trip from Harvard to Egypt in Raiders of the Lost Ark.) Those last three episodes were indisputably awesome, and I'm now rewatching the whole series in order to pick up on the many things I missed first time. It's already paying off, not least in the quotations from Goethe I just noticed on the walls of the tower block from which an attempted suicide takes place in episode 2.
Madoka's eventual wish and its consequences are wonderfully poised. It reminds me of the ending of The Homeward Bounders, though turned just a couple of notches more towards optimism. It reminds me of living.
I guessed fairly early what kind of creature Kyubey was, perhaps because I happen to have a written a Faust-based novel in which the Mephistopholean character is an alien who has been living parasitically on humankind since its first beginnings and offers magical powers to children. (There's a lot of it about.) But combining that with the Magical Girl story was genius.
Other miscellenous things I loved. The music! ('Sis Puella Magica' evokes the Mediaeval Baebes - in a good way. I can't hear it without crying - also in a good way.) And while it's a throwaway in the context of everything else that's going on at the time, the revelation that the reason magical girls (like so many other characters in anime) can get thrown around and hit without too much pain or injury only because they've had their souls ripped out is a wonderful touch. The tightness of the show is great too. Not a wasted character; so much tragedy, and not a villain in sight. That said, put me in Team Sayaka.
I think I'm really lucky to have seen this show simply because Amazon recommended it and I like Magical Girl shows so why not? I'd heard nothing about it beforehand and watched it in a totally spoiler-free environment, which I think must be the best way. But now I want to recommend it to other people, especially my daughter, and I don't know how to do so without giving away too much. She's not the kind to watch something like this (or like what this appears to be) on spec, even if we did have a massive Cardcaptor Sakura rewatch this time last year. I must give that some thought...