Both your brain and your heart are right!
The question is - which one should you follow?
To me, buying a car is mostly an emotional decision, and partly a cerebral one.
I've owned Japanese cars almost exclusively, and now after driving a Mercedes for almost a year, I can honestly say I can't see myself driving a Japanese car again. The Mercedes is just so much more solid and the engineering is so thoughtful, that the longer you own it, the more you see.
Participating in this site can also help you do things yourself, buy parts cheaper, diagnose problems, etc.
Life is short. Go with the Benz.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".