He's OK (hehe) in the jungle. He has a slow start into a really powerful late game. His first clear is reasonable, he can be easily invaded and his ganks are really powerful if done correctly. Also, he totally wrecks against full AD teams (unless they have Vayne). He's also getting a slight buff to his W, if that changes anything.
I don't see him being really too good top lane, but I know there's people who dig that, and he might be really strong against some champions. I think you should read a guide or two and maybe ask about the current status of the champion just to be sure.
Top lane is great if your good at using tp. Homeguard tp rammus is extremely scary. The problem top is that he's countered by a ton of champions so you might have a hard time farming, but just have your jungler gank you since your really good at setting up ganks with your cc. Jungle i'd say can be more viable in certain situations, now that Cinderhulk has died down, tank junglers aren't as good as they used to be, but no other enchantment is viable on rammus, so why go jungle. But his ganks are so good, you can get all three lanes going easily with just mobi boots and Cinderhulk. It all comes down to how you play as a jungler, there are three types; Ganking jungler, Farming jungler, and controlled jungler. Rammus is specifically meant to be played as a ganking jungler, if you play like a farming or controlled jungler, don't bother with him in the jungle.
I've mained Rammus until this season. He is very viable in the jungle. Does rather well vs devourer-jungler too as he can win the game with his early (and very powerful) ganks before they get sated.
He is **** when it comes to farming though so you really want to gank lanes.
I don't see him being really too good top lane, but I know there's people who dig that, and he might be really strong against some champions. I think you should read a guide or two and maybe ask about the current status of the champion just to be sure.
He is **** when it comes to farming though so you really want to gank lanes.