Are there 4matic drawbacks?

Are there drawbacks to having the AWD? Is the car slower, sluggish, less responsive? Is there a significant decrease in mileage? Does the additional AWD drivetrain cause more maintenance costs, or have reliability issues?
For the same reasons I do not want an SUV, I don't want to live with "significant" AWD drawbacks on the other 345 days a year.
Thank you for your advice.
As for reliability and repair costs, make sure you by a Starkmark vehicle and purchase the full bumper to bumper coverage for as long as you think you'll own it.






