Do anyone know or heard about it? From what I know, Wesnoth is kinda underrated and unknown, and I'd never know that if some people didn't recommend it to me. Battle for Wesnoth is also a turn based strategy game with some RPG aspects (such as leveling up your unit which works like a Promotion in Fire Emblem, with different branches to choose from).
The mechanic is very different from FE, although the RNG is still (if not more) bitchy (hitting something 4 times with only 30% of chance, what's this I don't even) and every unit has their own traits, such as Strong, Resillient, Quick, Intelligent etc. At first, there are only 5 (6*) factions (Humans, Elves, Dwarves, Orcs*, Undeads and Drakes), but there are many addons that allow you to play on new maps and with new factions (the most famous factions pack being the "Ageless Era").
Well, you see, I'm TERRIBLE at explaining shit. So, it's better to look at the Official Site. =P