I really enjoy CoffeeScript now. It is what I use for browser and node.js development. Before I tried it, I was somewhat skeptical of using it because I felt my javascript knowledge would fade or I might get confused about things, but I think it has enhanced my knowledge of JS because I don't just blindly use CS without knowing what the output is in JS.
I usually have the 'try coffeescript' dialog open so I can see what the compiled output looks like.
I trust CS to do the right thing, but I still like to confirm it's doing what I expect.
Same here. I know with vim you can have jslint run every time you make a change, so I wonder if that would work with the CS compiler, maybe even show an output pane. Though I don't use vim much, and spend more time in Textmate. Textmate does have a nice CS bundle, which you can do cmd+b to compile and see the output, but the window is not very pretty.