I just used them for a small project and was really happy with it. They provide just a couple environment vars attached to the process object and you're good to go.
I was talking to some of their employees at nodeconf this year and they explained that since Heroku only routes one request to an instance at a time, it essentially blocks on each request and you never get to actually leverage the concurrency of node.
I agree 100% with this post. I did shrooms 1x in Mexico with the most amazing weather, right on the ocean. It changed how I viewed things. It pointed out my social anxieties in that they weren't present. I consider it one of the turning points in my life.
My wife had something similar happen to her, a sort of before and after in terms of social anxiety and expectations. One trip cleared that up and the concerns have never returned.