I am a 1992 W140 owner, I have a 400SE, and unless you have lots of extra cash laying around just waiting to go to some mechanic, or own a MB shop, forget about buying that car. My repair bills make me cry, and are forcing me to trade my 1992 400SE baby for a 2003 S500. Although I will never have as awesome-looking car as my 1992 400SE, my wallet can't handle the uncertainty of the next repair bill, and I do opt for a certified pre-owned with extended warranty... This really makes me sad, as I said, I really adore the W140 body style, but now, facing AC and stereo amp repair bill, makes me wonder what will break next after I will spend $2,400 (best-case scenario) for AC and Stereo Amp problem...

There is no comparison between 600SEL and 750... BMW will always be BMW, and with that, it will always be inferior to MB, both in lush and in smoothness of the ride... If you choose 600SEL, I envy you, but get ready to spend some $$,$$$ to keep it to up to your standards...