[deadmanwalking]

It's been a while since I ate one. I got some donator days, (by luck, not all give anything assured)
You can get:
ap,ep maybe happiness refills
ranged or melee bonuses for next fight
more rounds on the next fight

Possibly more, but I rarely get many and didn't eat most of what I got. I hope that helps you. Last year they went around 100k each for the few that came up.