Been road cycling for a few years and I'm looking to pick up my first mountain bike. When riding with friends I've ridden a Specialized Camber 29er and a Bikes Direct Haymaker 1500.

I am 5'11", 165 pounds, about a 32" inseam
I have found four bikes I like and that fit my budget. Help me pick one!

1. Brand new 2012 Giant Talon 29er one. Hardtail, new, size Large-- $650
2. Used 2008 Specialized Stumpjumper FSR. FS, 26" wheels, size Medium-- $600
3. Used Radon QLT 7.0. German bike, FS, 26" wheels, size 18"-- $650
4. Used Scott Spark Comp 29er. FS, size medium -- $650