Javascript is overall cleaner than Obj-C. Both languages can of course be used and abused in many ways. Javascript is going to require less code in general. On the flipside, larger projects are harder to keep maintainable.

There are some trivial gotchas in Javascript, but same can be said for most languages. Most importantly weird type promotion system, variable & function hoisting and prototypal inheritance can cause some gray hairs. All those can be lived with, and prototypes are in some ways superior to "classical" inheritance.

C, C++, Java, Javascript, Lua(JIT), Perl and ObjC are languages I normally use.