Not at all. I find syntax highlighting awful for actual programming (it's sort of useful for the first few days of learning a new language). It makes code less readable, and encourages some of the worst practices of programming. People have written tons about this. At its best, it's a crutch.

I think code completion is more of a mixed bag. It's useful when you're stuck in ugly environments with FrameworksAndLibraries[withFunctionsLikeThese], but I just avoid those environments.

Also, people have built external commands that do code completion. They're not as nicely integrated, but could be improved enough to be quite comfortable, if that's what you're after. (syntax highlighting couldn't ever really work in acme or sam)