I want to suggest a feature for fast switch between Full and Mobile site view/useragents.
This feature is very useful in case if some sites 'mobile' versions are actually purely optimized or lacks some informations/features in theirs mobile versions (it happens a lot as for me).

Current Opera have this feature hidden deep inside setting. Chrome Mobile, for example, have this switch in main menu without need to even leave current page.
So, my suggesting is to do it the same way and put this switch to menu on address bar (where Share, Find, Translate, etc are located).

Thanks!