07, 08, 09 are all the same...no changes to the fork. For 2010, they have made some changes to the damper (added new versions).
There is the solo air.. fixed at 160mm of travel
THe two stem air.......can change travel in trail from 115 to 160 (cannot set anywhere in-between)
THen the U-turn coil...travel adjust anywhere between 115 and 160. Takes a few seconds to do (few full turns of the adjuster), but can be done while riding if you need.
As far as durability..air forks are always going to be more maintainance because of the need to have an air tight sealed compartment. Generally adding travel adjust to air has been a MAJOR issue with all companies.
The 2 -step air was rife with isues (and most were somply replaced by RS or converted to solo air or 2-step). Run far away from this model.
If you HAVE to save a few ounces, dont care about travel adjust, and are willing to do a little more service, the solo air is a good fork.
The U-turn is the simplest fork, and will prove to be the most trouble free.
Stick to the Mission control version (there were some OEM models with other dampers) and you have a very solid chasis with great tuning capabilities.
Keep in mind, that any new fork with small volumes of bushing lube will require frequent (very easy) service. Some tuners recomend bushing lube service every 20 hours of riding. That is most likely a bit excessive for most people, but will give you some idea of what should
be done to keep things in top shape.
Not sure of your price rangs, but this is a pretty significant discount on the U-turn: http://www.jensonusa.com/store/product/FK307A27-Rockshox+Lyrik+Fork.aspx