Vivaldi has at least one significant shortcoming worth noting. I prefer to put the Mac to sleep rather than powering off completely, and I usually leave the browser open. After several sleep-wake cycles--say, between five and ten--Vivaldi becomes unstable, necessitating a browser restart. (You'll know it when you have trouble closing a tab.) An overnight sleep-wake cycle will also affect Vivaldi's ability to display the day's browsing history; it can't seem to do so without a restart.
Also, if you want to block ads, you'll probably have better results with an extension or app than with Vivaldi's built-in functionality.