The award for the least appealing engine bay of all time goes to... The new Mercedes CLS.

I can understand it on a family hatch which has no premium or sporting credentials whatsoever, yet the CLS is intended to be chosen by those with more than a passing interest in cars, a sports coupe for the family (with electric driveway gates) if you may.
An inherent result of this means these buyers like to see at least a hint of engine to fuel their monetary reasoning, and unless they have earned their fortune in the world of high pressure injection moulding they are going to be bored to tears with the CLS.

On the plus side those strut tops look like dials to get in a safe.

See another rant about engine bays on supercars here.