I find JS works well as an OO-language, and falls short as a functional one. Not only when writing it, but also when it's executing. Dumb-as-rocks object oriented JS-code tends to have a smaller memory footprint, is less crufty, and is easier to debug. Functional JS-code tends to spam the heap, difficult for the JIT to optimize, and when writing it you have none of the compile-time safety of a true functional language.

Crockford succeeded in popularizing JS, partly by stressing the Scheme-like features of the language, but I'm not convinced that's where the strengths of the language lay.