Is it worth getting a diesel?
As the original owner of an '07 CRD WK, I'd have to say...definitely not! I just collected my CRD from the dealer after its second round of swirl motor/flap repair in the last year, and on the way home the check engine light came on again. Yes, the diesel will deliver HEMI grunt with better-than-6-cylinder fuel economy, but the added hassle (and cost) of maintenance, to me, just are not worth it...and that's assuming that you are lucky enough to get one that has no mechanical troubles. If you do a lot of research on here you'll find that, for a vehicle that only comprised 3% of WK production in '07, the CRD exhibits far more than its share of engine-related problems. I can't help that the engine is "a Mercedes" (woohoo). A garage queen is still a garage queen, and if you have to remove or bypass equipment that Mercedes or anyone else installs on/in an engine in order to get it to run reliably, then that engine is not reliable, period. I suppose if you enjoy tinkering and trying to solve problems with your engines, then you might not mind dealing with this combination...but me, I'm sick to death of this crap and when the vehicle is gone I'll be thrilled.
That's just the CRD part of the WK equation. As for the rest of the vehicle...it is now obvious that the WK was an under-developed design that went into production before it was ready for public consumption and, once in production, development stopped. My vehicle has had numerous electrical and HVAC issues and, along with tons of other owners on here, mine has had (nearly since day one) an unresolved ongoing intermittent severe drive line vibration. Drive train vibration issues are quite common in WKs, regardless of which engines are installed. Most folks have replaced (in many cases multiple times) drive shafts/u-joints in attempts to solve this problem, usually with limited or no success. Changing out my rear drive shaft only altered slightly the circumstances under which the vibration manifests itself. The worn u-joints that many have believed to be the problem are beginning to appear to be just a symptom that is caused by the actual problem(s?) farther upstream somewhere in the drive train...possibly a defective coupling between the transmission and the transfer case, etc. Nobody outside of Jeep appears to know for sure, and if Jeep knows they're not saying, they're just leaving us all to twist in the wind.
While there must be owners of CRD WKs out there who've had few (or even no) problems, I'd bet good money that most of them are unaware of just how lucky they are. It's very difficult to recommend a vehicle with this much baggage to anyone, so I'd have to say...choose a different vehicle. Obviously, JMO...YMMV