Well the Survival server is just that, survival. It is the original Minecraft. Amplified is survival with the terrain generator on steroids. (like seriously)
As for McMMO, it its essentially taking MC and adding a skill system to it. These skills go for many aspects of MC (Fishing,Mining, Woodcutting, etc.) As you level up you unlock abilities which help you.
I'm gonna say that you should probably take some time to experience each world as they have great things to offer.
I hope this helped you out!