Jimmy summed up Sandoval pretty well. I would quote a comment I read on Baseball Think Factory.
I ran a search on Baseball-Reference's PI, for players who stood six feet or under and weighed more than 230 pounds. The only hitters that came up were Prince Fielder, Bob Hamelin, Byron Gettis and Travis Snider. So at this point you have a player who's a switch hitter with a unique approach and a unique body type. What the heck do you make of a player like that?
As far as catching, I figure the presence of Buster Posey is going to make that a non-issue anyway. Sandoval is probably going to need to stick at third base to have value as a regular player. He may be better served in a valuable bench role, filling in at three different positions. I'm rooting for him. Unique, different players make the game more exciting.