I had the same dilemma and went with the 08 Rubi Unlimited, which I pick up tonight or tom morning. My decision came down to not wanting to get a second loan with an interest rate. I decided to take advantage of the factory special offered on 08s this month. I got 0%/36 month loan, plus $500 cash/3 yr free oil/filter service. I tried using invoice and factory rebate info to haggle a good deal beyond that, but ended up going thru the Costco auto program instead. I got the factory incentives plus a flat $400 over invoice price. So I actually did better than the factory offer alone, which is low/no interest OR $2000 cash, but not both. Thru Costco I got $2,295 cash off (figuring the invoice cost of my particular car and options). Chrysler gives dealers a straight $400 cash return on each vehicle, instead of bonuses for meeting sales quotas. Plus they do a 3% holdback, which the dealers (but not the salespeople) get toward advertising and other dealer expenses. I think the $2000 or low interest incentive end this month, and the military ends first of January.
Re the differences: As far as I can tell there aren't too many changes, but they include a little better made dash plastic, a hill assist system, and adding the power group as standard instead of being an option (at least on the Rubicon). Oh and they dropped the rescue green color (which I liked, but not many other do per the salespeople).
Hope that helps. I am still a noob so take it with a grain of dirt.