Looks to be Chromium based. No plug-in/add-on/extension capability yet. The desktop chrome takes a bit getting used to, but I could see the appeal of the simplicity. Menus and things are hidden, so it's a very uncluttered view.
Tabs show up on the right side. With a lot of tabs open it's hard to see what the pages are loaded in the tabs aside from the favicon. Probably tough for a power user who likes lots of tabs. There is a dual page view mode within the browser window, but I didn't see a way to open a new window. Looks like this is meant to be used full screen.
Too early to tell, but right off the bat I'm not overly impressed. It didn't grab me like Vivaldi did. However, I'm probably not the target market for this browser.