Pretty good. I like the armor stacking for damage. Also, Frozen Heart never seemed like an item to buy to me, I'll have to try it out. When I look at it it is pretty good.

I used to play rammus too, with a similar build. It's really good but very difficult high elo. Now i buy guardian angel after the boots and then pretty much everything you have depending on the enemies.
I find it's hard to make a stable build for rammus, it all depends who you are up against :)
But still +1