I've watched the entirety of both the FMA series, as well as Bleach (except for some of the fillers, it was just ridiculous), and I like both a lot, but I definitely feel FMA is superior.
Comparing the two almost becomes pointless, because even at the first glance FMA wins in pretty much every aspect.
It has a very well crafted story (in the case of Brotherhood, the 2003 series was practically a mess IMO (though still better than most of Bleach)), amazing and very life-like characters (Bleach does have a good bunch of nice ones, but they're difficult to take seriously), MORE LOGIC, and well, better production value. Though the latter is partly because in a show as long as Bleach it isn't worth putting the money in constant quality material.
Bleach is a series with great potential milked to infinity and logically raped by Kubo's writing. I would say I like the art style (art style =/= animation), but other than the characters themselves the art is mostly generic and repeatedly recycled.
That's as much as I feel like writing now, but well, you get the basic idea.