Also to OP I considered a c300/350 and you definitely just need to sit in and drive both of them yourself. I drove an 03 c320 before and it had every problem on the planet imaginable. I couldn't take it anymore even though it wasn't even my car and I was using it very cheaply so decided to save up for my own car. Test drove 2008 c300/350 and compared to 328/335. I knew the moment I drove the 335 that that was the car for me. Totally different feel. Aesthetically I think Benz has the edge on exterior design but BMW definitely better on interior. Reliability I can't really answer. My car has been fine for a year whereas my older Benz was a complete headache over the 2 years I used it. Not a fair comparison. Performance-wise I clearly chose the 335 but between 328 and c300 I think I preferred driving the manual c300 sport better (though I never drove manual 328, only auto).
Current: 2016 F80 Black Sapphire Metallic on Silverstone
Former: 2007 E90 335i Barbera Red on Terra Dakota