Go with the S500..I have owned both
and I will NEVER EVER EVER own another BMW. I owned a 70K mile 1996 740il and it was a NIGHTMARE. everything that could go wrong went wrong. The car had been serviced regularly as required by BMW but the oddest things would always go wrong. A/C display, suspension conponents, radiator broke, coil packs died, on and on and on.... Anyhow, I finally got the car to where I had replaced practically everything that could break and thought nothing else could possibly go wrong. Guess what, the engine developed a loud knock. A blown engine was right around the corner so I dumped it fast!! A year or so later I bought the same model year S500 and have had ZERO problems. It is such a joy to drive and I would not hesitate to take it cross country. Go with the Benz and save yourself alot of headaches and agony to your pocket book!!