Factions is more aggressive and involves raiding other bases, etc. Survival is in my opinion considered peaceful-factions. It's got similar things to factions like the involvement of parties, it's similar to creating a faction but its called a party instead, basically the same type of commands for making parties and factions. Raiding/griefing is not allowed on Survival and you will be punished if you commit those crimes, so just stick to the rules and you'll be good
In factions, u r able to raid other people's bases. While in survival u can't raid. My opinion survival is a bit more fun, bc u don't have to worry about ur stuff being raided. But it is fun to build region walls and cannons in factions.