If you have to get one or the other, get the 08 only because some "warranty" items will be covered. For example, weeping transmission lines are covered under 08's, but not 07's even though same part, same issue. They will not cover it for my '07. Personally, if you can afford it, get one within 3 years/36K miles so to take care of any warranty work. I am at 71K miles and have had about 4K in repairs since buying used with 44K miles 2 years ago, none of which Jeep would cover. Costliest mistake I ever made and will never make again, that is for certain.
Best of luck!