Oh I have owned both, MB's cost a lot more to take car of than Honda's and Toyota's. Parts for Japanese cars are cheap and everywhere. I can run down to Autozone and get an alt for a Camry for $100. Try that on your W140.
I4 Camry's and Accords are pretty easy to work on, the V6's are tight, but so is the M120, and M119.
They last quite a long time too, my 1993 Camry is still on the road and going strong, 170kish miles. Not bad for a car that cost $18k in 1993, cheap, cheap transport. Original engine and trans.
MB's are great cars, but I find they need $2k-$3k worth of stuff a year. Unless of course its pretty new and under warranty, or you drive it into the ground.