Count me in as another long-time Opera user who uninstalled Opera 15.
After reading this thread, I do resent the fact that when I went to get a copy of Opera to install on a newly set up Win 7 x64 machine, the website gave me Opera 15 without any warning that it's still a beta. I don't do betas any more -- haven't the time or the interest in dealing with the problems that sometimes come with them -- including missing features.
Thank you, Opera, for at least making the configuration issue fairly simple in Opera 12. I really didn't want to lose all my bookmarks and passwords. The bookmarks and Speed Dial came across from Opera Link OK, but not the passwords or site preferences. And I don't know what else didn't come across; that was enough for me. I just overwrote what was in the config files with the files from the old system.