As I was looking to buy, the dealer had a 2010 x5M with 5k miles for $80k. It was very tempting, but I went with the x5 50i in the config that I wanted.
Hard to make that call, for me it was extra insurance, extra couple $k dollars from my config to the M. Of course the M is phenomenal to drive, but so is the 50i. Additional I get one more year of covered maintenance without having to pay for extra coverage.
That’s just my reasoning and I love my x5 50i. With sport package or M package (which includes increased top speed) you also get to a respectable 155mph very quickly
So you could still take it up with various other luxury SUV's
