If you would like exact details of what is included in either/both of the packages, go look it up yourself at BMW sites.
To put it simply,
Sports package = brings car's sportiness up a notch (tires, seats, suspension, etc.)
Premium package = brings car's interior luxuriousness up a notch (leather, stereo, trim, etc.)
If you want performance and good looks, go with Sports package. Better yet, M Performance package.
If you want nice comfortable interior, go with premium package.
If you are like me, then M Sports package w/ SMG baby!