Bought it for my wife after testdriving and researching ML350 (2006), X5 3.0, RX330 and LR3 V8. Best value for money in the segment. Although the interior quality, fit/finish and "status factor" is obviously inferior to others in the class and so also is the ride quality, it's a compromise worth making in the light of better acceleration (especially in the passing range) than the others, initial cost for comparably equipped models, projected 5 year cost of ownership, reliability and versatility.
Navigation system w/ rearview camera, Useable cargo volume
Interior quality, more exterior color options, telescoping steering wheel, options for larger wheels, full size spare, quality of service in most dealerships (this was a major factor in the decision to purchase from my dealer despite significantly lower prices from other local dealers)