Kinda depends on the voltage you want to use too. MM handles up to 3s, some can do 4s or even 5s on earlier models, but need a BEC on anything 3s and up. The MMPro has the sensored option, switching BEC, and about the same current handling, but takes up to 6s. 6s@80A > 3s@100A (that's assuming those current ratings are accurate).
Also remember that the MMPro uses better FETs than the older MM, so even though it may have fewer of them, both ESCs have about the same current rating overall.
If I remember correctly those numbers were from Patrick. The Sidwinder I seem to remember that it was more closly related to the MMpro and it's contious current was also 80 amps.
Of course I have been wrong before.
Jeff
Correction: 120 for the MMM
MMpro is 2/3's the current handling of the MMM
The Warnings & Cautions discussed in this manual cant cover all possible conditions/situations. It must be understood that common sense and caution are factors which cant be built into this product.