Traded an '03 E320 for this '06 E320 CDI. The diesel is so quiet you don't know it's there. Plenty of power and lots of nice features like nav system and Harmon-Kardon radio, rear sunshade. Better cupholder/center console layout than the '03. Only had it for two weeks but well pleased thus far.
Fuel economy. Better than a lot of hybrids, with much more power. Range on a tank of fuel is over 700 miles. Solid overall construction and first class safety features.
Bring back the maintenance coverage during the warranty period. First service (oil and filter change, tire rotation and some visual inspections) was $ 329. Nav system is somewhat complicated.