Once you get past the layouts and color palletes, most browsers seem pretty similar. But what sets them apart is under the hood. Take Internet Explorer and Chrome, for example. Currently their main differences include Cross Platform Availability, Webpage Rendering and manufacturer.
Cool Infographic from Focus.com on what is HTML5 and why we should all care about it. I wrote a blog post a while back about the shift in interactive and HTML5 giving way to new experiences. Take a peek and throw me some feedback.