1. Main browser for two months now, but following it from day one.
2. 32-bit
3. Standalone
4. My general impression is very good. I'm a person that used Opera for years since version 10. Before their Chromium switch, it was a very unique browser with unique features (Tab Stacking, Tab tiling, speed dial, Opera dragonfly, Opera Turbo, Opera unite, mail client in the browser, (customisable) mouse gestures, notes, great bookmark manager with lots of customisastion options, themes, torrent downloader in the browser, chatbox support, rocker gestures, sidebar, single key shortcuts.... (you can look them up if you don't know some of them)). As a heavy Opera fan, I was dissapointed that they removed all of these features from the browser (exept from mouse gestures, turbo and sidebar), so I am happy that the original people who created all those great features (+Jon, the cofounder of Opera which is now CEO of Vivaldi) are working on it now at Vivaldi to make Opera 12 back alive but with Chromium, since it's unpossible to do it with Presto, the rendering engine of Opera 12. It's a bit difficult to imagine that all of those features are needed maybe, but only real Opera users from back in the day like me appreciate it even more that Vivaldi is there now. Still lots of work to do and not all those features are going to be implemented within a few months, but they are on the right track and adding these features gradually as they move on in the list. Unless Opera, which I used as standard browser for until 2 months ago, they are really aiming to restore those features. The browser is slighty slower on some builds as Chrome, but sometimes on another snapshot it's the fastest you can get. They are improving it each snapshot, so it's not a problem for me. The only extension I use is Adguard, since they will add all things I need in the future, so I don't need other extension at all. Still a lot of work to do on the browser, but as it is now, it's already quite feature-rich and it can only become better in the future.