Abandonment is the best for me. I like the close-range, urban fighting. When you're inside a building, it kind of cuts down on the computer-snipes-you-from-2-screens-away annoyance.
I don't like abandonment because overall I just don't like human weapons. AI is too cheap with them. It's also stupid that if you are standing in the building and the enemy rockets from underneath and hits the bottom of your feet, you die.