Presti will probably easily get 100 cents on the dollar for Harden. There is a severe lack of all-star caliber shooting guards in this league right now. I know that might seem hard to believe, but it's true.
You have Kobe and Wade... and then that's it. Who else is there? If you've played fantasy basketball you can back me up on this. There's a lot of tiny guards who are basically point guards like Westbrook, Rose... even Ellis and Steph Curry. Take look at the NBA efficiency rankings last year for guards:
http://www.nba.com/statistics/player/Efficiency.jsp?league=00&season=22011&conf=OVERALL&position=5&splitType=9&splitScope=GAME&qualified=N&yearsExp=-1&splitDD= Efficiency = Points + rebounds + assists + steals + blocks ... subtract missed shots and turnovers. ... After Kobe and Wade... who is the next best shooting guard? Surprise... it's Harden despite the fact he came off the bench most of the time and his team already has two BIG TIME scorers. Crazy, isn't it?? After that, you maybe have Joe Johnson and Eric Gordon. It's rough out there.
He's also 6-5 and 220 which means he's got legit size for the position (not a terry/bradley-esque 6'2 180 pound midget).
He's 23 years old. That means a team like Atlanta who is likely to lose Josh Smith... they'd probably gladly trade Smith for Harden. That means a team like Utah who has Favors and Kanter as their future bigs... probably doesn't hesitate for a second at trading Big Al for Harden.
OKC will get something major for Harden. Probably a star-caliber big man (maybe they'll dump Perks contract in the process) or a young stud still locked into a rookie contract for a while.