Ching...Thanks for the report and please consider the main key: Spare Tire?? BMW only use run flat tire and you may not have much choices. Also it may cost you a lot of trouble in the countryside.
If you want comfy go for Mercedes.
If you want sportiness and sheer driving pleasure, go for BMW.
Overall, I choose the Mercedes as it is more luxurious and relaxed to drive.
I drive C220 CDI for 3 years already. It is an excellent car especially for long distance driving @110km/hr. Also very economical. Car feels solid and quiet in driving. Surprisingly, not expensive to maintain.