After doing it the longhand way for over 10 years, I will never go back to that after using Haml. It just feels like the right solution to the problem of dealing with lots of nested markup. It might not be obvious what a benefit it is until you try it. I actually use my own custom-rolled flavor of Haml that is less Ruby-like, and I think it maps a bit better to the stylesheet and javascript.

On the topic of javascript templates, I tried Jaml for a while because I really wanted to have templates that could be cached on the client-side, but the function-based approach was really cumbersome. I ended up creating a server-side pre-processor that converts Haml to vanilla javascript functions that just build the output using string concatenation. These are called at run-time by underscore's template function. Overall, I'm totally happy with it so far.