The series actually finished last week, and I watched the final episode days ago, but it didn't quite hit home that it's finished until now, when it's Monday and yet I'm not waiting around for Eclipse to release the new episode.
The original FMA TV series was one of the first anime series I watched. My first five were Lucky Star, Elfen Lied, GitS: SAC, FMA and Higurashi no Naku Koro ni, in roughly that order. This being about two years ago. I really liked the first FMA series at the time, and I remember absolutely racing through the series, watching episode after episode, though I really didn't like the ending. I just felt it didn't really resolve anything or answer or explain many of the questions raised earlier in the series. As is fairly standard for series based on unfinished manga (Hellsing, Death Note...), it was pretty good up until they caught up to the manga, and then things go downhill as the series wanders off on a plot of it's own, which in the cases of FMA and Hellsing turns out to be completely different to the final cohesive plot from the manga.
The pacing of the first series is also pretty terrible, looking back. Things are strong for the first third or so, when there's manga, but then it slows down massively, and very little really happens or gets revealed for about twenty episodes. Then suddenly it rushes into the ending and it's all over with just a few more episodes.
On the other hand, Brotherhood is fantastic. It's what the first series should always have been, and it's a fantastic remake that stays true to the manga (which I've not read) right up to the final episode. It just blows the first series out of the water, and really just goes to demonstrate how poor it really was. The animation is much better, the pacing is excellent, the plot is cohesive and there's a proper ending and conclusion that wraps it all up. The characters are pretty well developed, and as a whole it's just so much more well-rounded than the first series.
It's a really fantastic series, and it's a little weird that it's finally over, after more than a year of following it week after week. Like the original FMA series, I'd also say it's a pretty approachable series, and I'd recommend it to people who haven't watched much, or any, anime. It's got a really good mix of story, action and humour, and some of the characters (mostly Alex Louis Armstrong) are absolutely fantastic. I wouldn't say it was necessarily spectacular, as in I don't feel it does anything that hasn't been done before in a series, but it does it well. It may not be exceptional, but it's still very good, and importantly it's consistently very good throughout the series, which not many anime manage to achieve.
For people who watched the first series, unless you really hated the general premise, you should really watch Brotherhood. It might seem a bit crap for the first fifteen episodes when you're getting the same plot you already know, but once you get past that it's more than worth it. If you really care, just skip the first ten episodes or so, but really even watching from the start as I did, it's still not that bad because it progresses so much quicker than the first series, and it's subtly different as well.
So yeah, for people who don't like waiting for each episode to come out, and prefer to just watch series through in one go, it's finished airing now, and it's definitely worth checking out.
For people who have seen it, there's also some OVA specials that most people don't seem to be aware of.