Pros
As others have said, free donuts/soda/coffee while you work, 50% off discount for everything in the store for you and friends/family while they're with you. Relatively simple/easy work for a food service job and regular raises for people that stay with it for a little while. Talking with people while they visit is nice when business is slow. The management is supportive and there are several little gifts that are given to the staff regularly.
Cons
Friday/Saturday after the hot sign comes on, it can get to insane levels of of people coming through the door and when you're understaffed or the doughnut machine simply isn't making the glazed fast enough, it can seem hopeless to get everyone in and out without getting yelled at by a customer that can't fathom that they have to wait for hot doughnuts for 5 minutes or so.