See the Opera Mobile blog for a list of new things in the 11.1 and 11.5 versions (not everything applies to Maemo though).
Opera Mobile 11.5 for Android change log Added Data Usage view Implemented adding bookmarks to Home Screen Implemented support for inline HTML5 video on Honeycomb devices Implemented import of system bookmarks Fixed problem with Cookies disappearing during the browser session Fixed problem with Out of Memory when login to Link account Fixed problem with Flash not working on HC devices after 11.00 update of Flash player Various fixes for font problems Various stability and performance fixes Cache stored on SD Updated Mobile core to 2.9.201 Permissions: See
Specific to this version is a few new keyboard shortcuts: CTRL-E Activate search box CTRL-I Zoom in CTRL-O Zoom out CTRL-B Go back in history CTRL-F Go forward in history CTRL-S Stop loading page CTRL-R Reload page Enjoy! /ohrn
P.S. For all you user agent changers, there is a new easy to use option in the advanced settings to mask as desktop Opera.