Seed Mail alternatives

Actually I'd like to review browser more than calendar, because calendar is more simple by design, but the browser is more important for me as Internet user. I have used both Vivaldi and Opera. My experience with both has been positive. I like how much personalization you can do with the two browsers. It is a little more difficult to find settings in Vivaldi than Opera, but once you find them its not that much more difficult to change. I would say that after using both browsers for a while I prefer Opera.