Similar experience to mrclose here. I just upgraded from version 12.x The worst bit is this: I read my news online. Now some news sites are full of flashing animated banners and ads - stuff that can trigger epileptic fits and migraines in some of us.
In Opera 12 I had the facility to suppress unwanted content like that. Well, that facility seems no longer to exist. Nor, for that matter, did Opera 25 take on board information about stuff that's making me sick. Everything is flashing and sliding and blinking. Making me sick.

I hadn't even noticed the absence of the auto-login feature yet. That's a deal-breaker, too.

Won't be using it. I can see no advantage to Opera 25 over 12, only disadvantages. In my opinion it's a downgrade, not an upgrade.