AllEyezOnMe & shawncampos2k4 must be brothers, you have the same IP address and same xbox handle, that can't work if you want to play in league's.
i personally like the curved slice because im generally a baseliner and if im on defense, a well placed slice added with curve throws them off and gives me the upperhand. if you're a serve and vollier, topspin might be better because a nice topspin volley will curve away from ur opponent making it even harder to reach. i recommend those 2 skills over anything else...