Though its features are nice. I threw my allegiance in with Opera. 'Cause it was the first one to remember my tabs when I closed the browser.
Firefox can do that too, if you enable it. :P

The process thing is intentonal. It works by turning each tab into an individual process, so when one tab goes horribly wrong, only that tab needs to be closed. It's a cool idea.

I have no idea what to tell you about the scroll button though. xD It works for me?