Palpatine was way smarter, so maybe he'd see Magneto coming a mile away and have something planned. I mean, they're both susceptible to explosions-- so Palpatine could see in to the future and have something rigged, I guess. But in an actual dual, Magneto wins hands down. No matter how strong Palpatine's "force telekinesis" is, Magneto's ability to control metal would punch holes through his powers. More importantly, the light saber is made of metal, giving Magneto a solid edge up over Palpatine.
~String