Just tested opera mini, on my iphone, and there are a few issues. The search field is aligned to the top of the page. There is no place holder text. There is no search suggestions list. There is no way to execute the search. This was with UA id 38.
Topic on Talk:Wikimedia mobile engineering/Mobile QA/DeviceType Changes
Thanks for helping out!! Would you mind creating a bug with this in bugzilla and put "device type" in the keywords section?
Thanks, Derk-Jan - however, it behaves the same for me on enwiki, so the new system is not guilty in this.