the boss units are essntially stonger variants of regular units. Think of the "Hero" units from starcraft. The boss battles themselves are not super epic as they are in final fantasy. They take strategy, but in a different way.
I believe there is a downloadable demo of fire emblem from the 3ds store. The best advice I can give you is go to youtube and watch gameplay videos to get an idea of the bosses.
This is my 2nd fire emblem game, the thing I like most about it aside from the field strategy is the characters and how they all fit together.
Don't know if that will be a helpful response for you TC, but thats my 2 cents.
Basically SRPG VS 3rd-person action Hunter genre game
I like both, but I've already played some variation of MH3 already, and it doesn't have online (something that really improves the game) unless you ALSO have a Wii U to act as a router, so I'm just waiting on Monster Hunter 4 instead (which does have "proper" online).
FE:A is solid SRPG that will easily keep you occupied.
People who've needed "a monstah to clobbah dat dere Kirbeh!": 128 http://img23.imageshack.us/img23/15/heartscream2.jpg