The front brakes had to be replaced at 24K miles. At 40K miles the back brakes had to be replaced. Prior to this, I drove a Lexus for 60K miles before the brakes needed to be replaced. We will be going back to Lexus and I hope I never live long enough that I am forced to purchase another Mercedes-Benz. Dealers have only been marginally helpful and say this is reasonable wear - might be but isn't for a Lexus.
Just bought the E550 4matic a week ago. Love the car. It came down to the audi A6 or 5 -series. This car is much better in both build and drive. The V8 is very fast and smooth. The HK sound is awesome. The Xenon lights are great! Once you use them, you won't like regular lights again. The only things I haven't liked is the COMMAND function. It's ok to use. More complicated than it needs to be. The IPOD interface could be better. I got the sport edition. Not much difference in ride quality between sport and comfort modes. The car height feature is pretty cool when parking near a curb. It raises the car about an inch so you don't hit some concrete curb when you park.
Sound system is a 10! V8 engine. Interior and ext are excellent. Chestnut brown leather is much better than standard color leather. Lights. Keyless entry is cool.
The seats are not as comfy as the 5- series. More firm and ergonomic. Don't know if this is in sport model, even with drv contour seats. Seats little better after 1000 miles. Folding side mirrors. Better ipod function. ie play radio through iphone, improved track selection and not through glove box
Very smooth, solid, comfortable and quiet (almost eerie-quiet with audio system on). Previous car was a BMW 545i and it's better in almost all respects. Particularly surprised at how quick it is and how well it handles in sport mode; would really give my 545 a run for its money. Also like the feel of the power steering better; much more variable; does not feel as "heavy" as BMW steering at low speeds. My car has just about every option except driver assist. Only major disappointment is the Night Vision system. The infrared camera is really just a grainy B&W camera; there's nothing infrared about it. My eyeball detects deer and animals much better than it does; almost distracting.
Instrument cluster design, sport steering wheel (awesome feel) , two- tone interior, drive-dynamic seats (a must), panoramic sunroof, Indium Grey color (different, classy) hood ornament (classy), LED interior lighting (though they should have done the footwells), overall exterior and interior design
Brakes are weak compared to BMW; just don't have the same clamping force/confident feel. Nigh vision is useless; almost distracting; waste of money. iPod connector doesn't charge the device. Interior plastic a little cheap looking. Footwells should be lighted (somewhat) when driving at night.