Hi there. I have downloaded new version of Opera just to see how it will fit my expectations. And there are only positives about it. This program uses the same engine as Mozilla does for rendering web page fonts I could notice. Also there are a lot of settings I guess, because there is no way that I can find where to adjust cookies behavior. It seems like Opera is deleting cookies on each program end.
Opera's interface is very tricky and getting to the setup preference point is quite hard sometimes because of that. I am comparing it with Firefox, nothing else. You have Quick Preferences and just preferences. Tools>Preferences>Advanced and then Cookies on the left side. There you can manage what you want regarding cookies.