BSG is easily orders of magnitude worse. FMA just kind of... fizzles out in a lame manner, without adequately explaining some of the core mysteries of the series. Or maybe I was simply too dumb to understand their explanations? Regardless, it's still well worth your time for the great characters, great music, great animation, and decent story. It's fun and light and worth pursuing if you have the time for it and enjoy anime.
To be honest, my biggest complaint with FMA isn't the ending, but the fact that the series straddles this strange line, where it deals with very mature content and often in a very mature way, but then practically no characters actually die, leaving it feeling like a kid's show in adult clothing.