Seems worth it to me. There are all kinds of nifty things you can do with it. I was going to get an MP 20 but I opted for a tunze wavebox for my new setup anyway. I have the room for it.
In a 30 gallon though, that is a different story. I think that the smaller footprint of an MP vs a koralia is a good idea in such a small tank. You need all the room you can get.
If it were me, I would get the Mp10. I don't know what an ES is. Can't help there.