Well, kind of.
As of the latest release, 24.0.1558.3, Opera on Linux has support for system borders, but it seems to only work if you are running under a session other than Unity. Also, Under Unity, you still get right aligned Window controls no matter what setting you've chosen. This should be terribly hard to get used to, but it is a little annoying.
Otherwise, Opera on Linux seems to be getting much more stable (apart from occasional rendering issues where entire pages are invisible). I have yet to encounter a crash after probably an hour and a half (or close) of constant usage, compared to the previous situation, where Opera would crash every few minutes for no apparent reason.
Still missing, are many of the features that once made Opera great. There is also no word on whether Opera Mail will ever make it to Linux, which is sad considering the rather limited availability of really good desktop mail clients on Linux.
Download the official 2buntu app for both Android and Ubuntu Touch.