It was a good experience when I returned my X5 in 2011. I did get charged for some cosmetic damage, but I knew I had a few dings. It was pretty cheap. The tires were also about ready to be replaced, but they didn't charge me for it.
ED on 7/18/2014: 2014 550i, Space Gray, Mocha. M Sport, Cold Weather, DAP, Executive, Lighting
PCD on 9/6/2011: 2011 550i, DSB, black/oyster. Prem 2, Conv, Ventilated, HUD, Sport, DHP, SAT