I just started using Vivaldi and the first thing I missed was the ability to Pin Tabs to my favorite web sites. This is a feature I would like to see asap. Otherwise, it looks interesting and I look forward to see how it evolves. Are there going to be addons? A video capture addon would be good also.
well, I might just not to tell everything sooner than it's released but since no one have told me not to…: pinned tab will be there really soon. Probably in a week or two (since releases are weekly).
about extensions (addons): already working from https://chrome.google.com/webstore/category/extensions
also try to write: vivaldi:extensions in the address bar and see