Yeah, Wiktionary calls the English loanword (without umlaut) /ˈuːbər/ and the German /ˈyːbɐ/. I think it's been a fairly ironic productive prefix in some people's informal English for a while, often hyphenated, like "uber-cool", "uber-interesting", ?"uber-dangerous". (Latin "super" is cognate with German über as well as Greek "ὑπέρ" (hyper)!)