This map is simply a hollow sphere that takes up 8 visleafs (yes it works). It has 16 spawnpoints, none of which are team-specific. The spawn points lie high on the sides for initial speed to the control point at the bottom.
Here's some tips by class:
Scout: Speed isn't really necessary on this map so much as damage, so scout is a little obsolete.
Soldier: Best from above. Rocket splash damage and force easily cut down on players grouping on the point.
Pyro: Combined with speed gained from gravity, pyro is basically w+m1 on steroids. One fell swoop can take out an enemy in a second.
Demo: Good on the point, better above. Slope allows you to aim above higher enemies and let the timer go off on them. The Iron Bomber is especially good from above.
Heavy: Very effective for capturing with any minigun due to damage falloff mechanics.
Engineer: Very limited building abilities due to slopes. Not recommended.
Medic: Obviously a good choice considering the long cap time.
Sniper: Able to jarate from a good range up above. A crossbow may be effective at close range.
Spy: Close quarters and very visible. Be cautious.