He'll be like a Marcin Gortat or a DeSagana Diop. He's decent, but then someone will wildly overpay for him, because that's what you do with bigmen. I would say he's potentially better then those two however.
Ever since I heard about him in the draft I thought he has mad potential. VERY athletic, strong, good shot blocker and a good hustler. He was the most athletic player in the 2007 draft (he was drafted in 2009 but his measurements are from 2007 draft)
As someone else said above, Camby is the best case scenario, maybe stronger But I think that is who he should model his game after. Kemp was an extremely smooth offensive player, and I don't see Serge with that kind of ability.
We have him locked up 4 more yrs for cheap, including the last 2 being player options. He was born in 89, so he will still be young enough after that to get his ridiculous Dalembert/Chandler/Okafor-esque big men always get overpaid extension.
Main thing I like about hm that he did this series was his defense on Lamar Odom. Somebody finally figured out Lamar is left handed and if you overplay him and force him right, he doesn't do anything.