LOVE the X5M!!! The power is insane but the handling is what got me. Handles like a 3-series car except you can run over curbs and stuff also lol...while carrying 5 people, a dog and luggage. Launching the thing from a dead stop is rain is sooo much fun as well.
Almost just bought one for my wife (I have 2 cars already) as I was looking for a vehicle with a 6,000+lbs gross vehicle rating for an accelerated tax deduction and the X5 qualifies
In the end just couldn't justify the extra cost of the M for the wife (who doesn't even work and just drives to the store and yoga) so I went with the non-M version.
Stock it's faster than the M3 in certain situations....off the line, and at low RPMs. Definitely better in traffic and as a daily driver.
Go for it bro.