Who wins?
Skeleton vs Slime
Slime wins 59% to 41%. 35 more put them in the same row. From Minecraft Mobs Tier List. Pick a side.
grumpy_pickle on Skeleton: bones for bonemeal and the skeleton spawner farms are great
WetDumpling84 on Slime: slime farms in swamps at night give you sticky pistons, not as useless as people think
Minecraft Mobs Tier List: the full ranking