Vivaldi is developed by a team created by the former Opera founder and CEO. Vivaldi kind of tries to re-create the spirit of Opera, but I think it's going to be too hard to do it.

For those who didn't use it, Opera was first a paid browser (which limited its reach), then an ad-supported browser (which again limited its reach). It then finally became a free browser but by then it was too late.

It had its own, super fast, rendering engine (I forget its name, Presto?). It had a built in email client, feed reader, calendar (unfortunately with no Exchange or Gmail integration), a notes app, a powerful download manager and even a Bitorrent client. And a TON of features and UI flexibility.

It was super compact, a marvel of engineering and UX design that managed to pack all those things in a package of about 5MB at the time, and you wouldn't even see or load the extra functionality like the email client if you didn't use it.

Unfortunately with HTML5 and the Chrome-ification of the web, it couldn't keep up :-(

Vivaldi tries to do the same on top of web techs and web techs just can't handle it. Web techs are almost as flexible but they're really slow and bulky.

Still, I wish them luck.