I love both, but I say Sindel obviously.

She has the mystic powers, speed and she is smart.

Sheeva has the muscles, and speed.

Sindel rocks!

Sindel is the best, she would whoop Sheevas ass. I mean i think Sheevas really cool and everything and would love 4 her to return but Sindel seems to smart and quick for sheeva. The only thing Sheeva has on Sindel is he little stomp, when Sindel can fly and shoot shit, not to mention her deadly scream. Eaither way Sindel and Sheeva would never have to fight because Sheeva is Sindels body gaurd so Sindel doesnt have to deal with the dirty work. Sindel is the best!!!

I say Sheeva, just an educated guess, i have no clue who would win. Both have there advantages.