Scores generally seem to go up significantly faster in this play mode, and the dynamics change a bit. With only one flag, when your team has it you have nothing to defend at your base, and the other team has nothing to go into your base for. Everyone is concentrated on either moving the flag into the scoring area or stopping the flag and the other side as that team is bum rushed. The flag is located centrally, and it is generally pretty easy to get once it's there. This play mode seems to award the advantage to the most cohesive team, as there is less opportunity for one man to just go and score by himself.
Overload is even better.
This one can become really interesting. In the first two styles, the goal is simply to get into the enemy stronghold and either grab the flag and run or just score your point. But in this mode you spend a little time in the base. Destroying the enemies' steel skull isn't easy. And all the while, your opponents are spawning in, trying to blow you to smithereens.