Though Wikipedia traces its origin to a 1979 episode of Saturday Night Live, I have become aware of the use of the prefix uber- in English-language media (mainly American, as far as I know) only over the past decade. It is, of course, based on the German über, and some publications (such as The Nation) do in fact apply the umlaut sign, but in speech it never sounds as in German but invariably rhymes with ‘goober’ (Wiktionary gives this as the default pronunciation).
What I don’t see is what meaning this use of uber- carries that is not conveyed by the traditional English (or Anglo-Latin) super-, other than showing off the user’s supposed sophistication. (In German über has very different connotations, as discussed here.) After all, ‘Superman’ as a translation of Nietzsche’s Übermensch was good enough for George Bernard Shaw and Jerry Siegel. Who needs more than that?