I personally think the C Class exterior is best in its class. The design is well thought out, unique, and flows together very well.
I like the variety of powertrains available. The choices give you the right control over the vehicle and all choices are responsive enough for safety.
The handling really is unique. Only a Mercedes Benz has the unique mix of both luxury and sport handling that makes you feel like you are both hugging the road and gliding at the same time.
Mercedes has long been an innovater in safety. Being the first company to introduce many safety features into its cars such as the airbag. Having been thru a minor ice caused accident, I can really attest to how safe I felt.
The materials used are luxury with well attention to detail. The interior leather & controls age well and do not feel cheap. The engine is well laid out and does not feel cluttered as some engines do.