This is my 2nd X5 and I have never had a problem except with sticking doors in both of them. Speaking of doors, they are heavy and close by themselves, knocking women and smaller men off their feet. Is it worth the safety they provide? Your preference. Ride is amazing. Visibility is too. No need for the 4.4, unless you want to dragrace on the interstate.
Doors too heavy and stick, especially in winter. Trunk is cumbersome to open. Upgraded stereo is lame.