For me I say Longbow is my favourite map so far. I just like Snow maps. Like Avalanche in Halo 3. Breakpoint in Reach is my favourite Reach map. (Maybe I like the snow cause Im Canadian? lol)
But as for Exile...Im my opinion it looks like a bigger version of Beaver Creek, and I hate Beaver Creek. I dont think I have ever won a game on that map unless it was FFA lol. Also kinda looks like Highlands but at the bottom of a canyon...