According to this JSBen.ch test, the switch setup is the fastest out of the provided methods (Firefox 8.0 and Chromium 15).
Methods 3 and 4 are slightly less fast, but it’s hardly noticeable. Clearly, the if-elseif method is significantly slower (FireFox 8.0).
The same test in Chromium 15 does not show significant differences in performance between these methods. In fact, the if-elseif method seems to be the fastest method in Chrome.
Update
I have run the test cases again, with 10 additional entries. The hrefmap (methods 3 and 4) show a better performance.
If you want to implement the compare method in a function, method 3 would definitely win: Store the map in a variable, and refer to this variable at a later point, instead of reconstructing it.