Fire Emblem has always been a favorite video game series of mine, and I enjoyed the OVA a lot. I understand that a lot of people are turned off by it only having two episodes, but... it's an OVA, not a series. The story is really only about Marth's (or Mars, in this dub) past, a precursor to the first Fire Emblem game for NES (now on the DS, also), while the rest tells a version of the beginning of the game. I think it gives a good insight into Marth's past and character, but I especially liked the parts that were directly (somewhat) from the game, especially the second episode with the priestess. To me, it really was the video game being represented accurately. The animation is good, but I'm just a fan of this style and the time period this was made. The voice acting is mediocre, save for Mars himself, voiced by Spike Spencer (Shinji Ikari in Evangelion). As for character development, the main characters are done well, but the secondary characters are just thrown to the side, and those who are not familiar with the game would be very confused as to who they are.
If you're a fan of the video games or just curious to watch, I say give Fire Emblem a shot. It's a lot better than most people think.