I have a 1988 Cherokee approaching 300k miles, so I know and love Jeeps.
I bought a 2007 WK Grand Cherokee with the 3.0 CRD Mercedes Benz turbodiesel that I owned for the shortest time I've ever had a car in my life -- 2 months and 1200 miles. Sold it at a big loss, and I've never looked back.
The car was delivered with at least 7 things wrong with it -- from minor issues like roof rack trim falling off and speakers that wouldn't work to more major ones like windows that wouldn't go up and down and suspension that creaked over every compression/rebound. A trip to the dealer to have these addressed resulted in 0 for 7. A combination of not observing the problems, claims of repair (that made no difference driving off the lot), and parts theoretically on order for a callback that never came (and parts that were never ordered on re-checking). This was going to be a bad experience for a long time to come, I felt. A combination of lousy quality on delivery and horrible after-sale service was going to make getting it right a long slog. I just didn't have energy for it.
I still have the old Cherokee, but I'll never again visit that dealership, and can't imagine buying another Jeep.
Maybe it's just products from the Jefferson North assembly plant, which doesn't have the best reputation. I'm delighted to hear of folks with great experiences with their JK Wranglers, and wish they had more headroom. Just my 2 cents, I know, but for what it's worth, I'm in agreement with the survey results.