Ok, so most people know the main things that are better about it; Minetest is free, easier to make mods for, has a taller world etc.
But there are a few smaller things that are really nice:
- Mesecons have more features than Redstone.
- Full crafting grid in inventory.
- Not losing your stuff when you die, no hunger.
- Mese, Nyan cats, etc.
- You can dig a mineshaft straight down and the bottom will be lit up by the sun.
- No launcher, no logging in with your email.
- Better protection mods, less over-protection
- It's actually kind of good that Minetest is less popular:
- not blocked at school
- servers aren't too crowded
- in-game list of servers is possible
- lots of good usernames available (In Minecraft, apparently someone else is using "12me21")
- better community