I like Ivory Tower. I just hit up Magnum/SMG until I get to the top, then if the Sniper is open, I just started picking it up (It is actually super easy to Snipe up there since the area for opponents to run is so small).
I hate Burial Mounds.
I don't really like Ascension, but I just found out last week that you can take the Banshee to the top of the really tall towers (Above the two main Sniper towers). I haven't been able to snag a Sniper then grab the Banshee to get there in a game yet, so I don't know if this is common, and useless knowledge.
I don't really like Beaver Creek, but when I play there with my roommate, we just chill behind the base (Both with Magnum/SMG combos), and double team anyone that creeps around the corner (We both look in other directions to get each others back). When you play against good players though, they rarely run in groups smaller than 2 and usually 1 has the rockets, which fairs well against us..
I have to be the best Level 10 in XBox Live. I swear.. I get the shittiest party members.