My wife recently returned a leased 2007 MDX and purchased a 2010 X5 35d. The X5 is hands down more fun to drive, quieter, smoother, luxurious and fuel efficient. The X5 handles like it is on rails and the quality of the interior is superior. The MDX center radio stack with over 60 small and unorganized switches was a nightmare since it was very difficult to find the right switch for changing the AC, heat, audio, defrosters settings. The BMX ergonomics with the IDrive are much better to include the voice controls. The MDX didn't have rattles but had excessive road noise and the engine wasn't very smooth. The straight six BMw engines are so smooth. The MDX did corner well with the super handling AWD. In the 45,000 miles the MDX only had a few problems (nav traffic computer failed, chrome came off the front grill, check fuel tank cap warnings, and the front hood would flutter excessively when driving into a head wind at highway speeds. The flutter is a design flaw. The hood needs to be stiffer. There was a service bulletin for the flutter but it didn't help much MDX is a Honda and IMHO the extra 10K for the BMW is well worth it.