Smith is a nice QB. He's athletic, very smart, very accurate and has a nice feel for the game.
However, he doesn't have an arm that's going to allow him to go over the top of defenses with regularity.
He's most likely going to end up in Arizona as he's a west coast guy originally, but there is a possibility of him in Kansas City, New York Jets, Jacksonville, Oakland, San Diego (there's a lot of fans beginning to really get vocal about Rivers and his shitty attitude and inability to get anything done in the red zone year after year), Dallas (see Rivers), Cleveland or even Tampa Bay, where Freeman looks to have regressed but there is talent around him now.
Right now, I'd put Smith's list as:
Alex Smith is a major upgrade to anyone we have on the roster, but I'd much rather have Geno, sign Jason Campbell (who is a UFA that has nice skills, a good arm and experience in the league) and draft another guy in 2013 in the later rounds. As it stands, I think Campbell would be absolutely perfect in Reid's offense and is at the point of his career where he'd take that backup role to a guy like Geno.
In this day and age, you've got to have a guy who possesses the threat of taking the top off the defense. Geno has displayed that numerous times throughout his college career.