The literal translation to "competence" just sounds sad. In english, you'd never use the word competence in any sort of marketing because it should be self-evident that anything you're promoting is already competent.
Linguee also gives a translation as "expertise", which would be much more acceptable in an english slogan. (I haven't tried this on DL yet).
It could be used as an election slogan, however; oftentimes slogans for parties or candidates are about how terrible the other things are and how only that candidate is good enough to fix it. So, the slogan would imply that this candidate is the only one with competence to fix the problems that the others have created.
The dictionary says Kompetenz also means responsibility, which makes a lot more sense in the context, but I got dinged for it.