Minecraft which is better protection 4 or protection 1?

I often play Minecraft on servers and there I sometimes find protection 4 or 3 iron armor, sometimes protection 1 or 2 slide armor. My question now is, should I use it? So if I get slide protection 2 armor, I use it, but if I have slide protection 1 and iron protection 4 armor, which one do I use?

I would always use the better material, i.e. Diamond

Dia protection 1 and an iron protection 4

I would choose iron armor

Protection 4 iron is better than protection 1 slide. So I would take iron. Dia looks pretty nice xD

I would take dia with protection1, because in my experience iron with protection 4 or 3 protects about as good as a slide armor

Protection 4 iron is better