Today was curious and tried to trace what program the ubuntu tool runs & it seems it runs something like "software-properties-gtk" but after this no info on how to install or does it actually chooses best repository server.
let me know if there is some similar thing in Mint.
Edit: installtion of "software-properties-gtk" does provide this functionality. And it wont remove any linux mint repositories. Just updates ubuntu repositories with fastest mirrors.
Ah...., now atleat I can happily go for frequest updates or installtion of softwares without worrying about waiting for hours...






