I have 4 small children and I needed a car that would seat all of us. I must admit I wasn't thrilled with the looks of the car and considered it only because it would hold everyone in relative comfort and because the 2008s were on the way and the dealerships had boatloads to get rid of in late July. Having come from a Volvo V70R, I had to have the V8 and not the V6. While the R500 is a great choice for someone with 4 kids, it is nowhere near as responsive or fun to drive as the Volvo. To be fair, the V70R is the Sport version and the R500 has never pretended to be remotely sporty - unless you want to lay down 80 large for the AMG version. After all, its a glorified minivan/station wagon.
I like the integrated radio/phone system.
Include Bluetooth module instead of selling it as $400 addon aftermaket option. Move cruisecontrol farther from turn signal. Fix defective rear hatch issue. All and all the vehicle is fine. I expected more from MB coming from a Volvo. MB expects you to pay for many items that should be standard