[leeah]

As a owner of 2003 S430 4Matic, I do not see the difference when it comes to a daily commuting driver. If you want more room for performance and options, go for S500. If you want economical(gas price) and don't mind the 27BHP differences and if the price difference is significant, go for S430. Maintenance and reliability will be almost the same since these cars are equipped with notorious Airmatic suspension and 16 plugs when its time for tune up. Later year model will be the key no matter it is S430 or S500. I used to own 2001 E430 and the difference between E and S class is pretty significant.