Google Chrome is the most used Web Browser.
The second most used Web Browser is FireFox.
I myself use FireFox web browser as I find it easier to use and less resource intensive as well.
Google Chrome seems to use more RAM than FireFox web browser.
The most popular current browsers are Microsoft Internet Explorer, Google Chrome, Mozilla Firefox and Apple's Safari.
There are also more mobile web users today than there were before.
So if you have a website and don't have a mobile website theme that displays good on mobile devices then you will lose some traffic.
The majority of my website traffic to my blog is through mobile devices and Google Chrome on the mobile devices is the most popular web browser for the mobile devices.
I also get a lot of desktop users that use FireFox web browser but also the majority of those desktop users are using Google Chrome.