I agree with BirdofPrey. It is disappointing the option to save sessions has been removed when it was also one of the only reasons I stayed with Opera while all the other browsers have been making, and continue to make massive improvements over these past few years (while Opera stayed same old... Opera).
Yes Opera 17 it is considerably, but doesn't come close to being an improvement on it's previous versions with all the snipping and cutting.
An option for other peed off users is to keep and older version installed on your computer, and a new one. When you want to open/save sessions use the old browser. When you are just surfing and want speed use the new one (or any other browser...). If you aren't in the old Opera, and want to save your session just open it up, copy+paste the webpages into the tabs and save session.
Yes it takes a few moments, but it works. It's either that or install Firefox/Chrome's clunky saving session extension.