Ducatirider,
I don't know how the Raven 1 compares to the Mambo. But theoretically, I think the motor of the Raven One is much better than Mambo and this could likely make it sound better. People in the know beleive the direct drive TT's (Garrard, EMT, etc) are the cream of the crop. The Raven motor behaves close to a direct drive in torque and speed control.
My points about the AC vs the One where more relaible since they were in the same system, aside from different cartridges and arms. However, the AC had a better arm and cartrdge on it. I think they are close enough given the 5K price difference. If funds are an issue then go with the Raven One. The AC is better but as you know, the law of diminishing returns applies like it does to most gear.
I'm not sure about sleave lengths.