Benchmarking of Hardware for the browser performance may depend a lot on the content of the website that is been accessed by the users. Surely it will help the buyers to understand how good is hardware.
End user experience is no doubt the most important information of benchmarking browser performance. User experience will break down into different areas.
1) Network performance
Network performance can further breaking down into latency and packet loss rate.
Rendering performance will likely be affected by the technology being used such as Adobe Flash, Adobe Air and HTML5, etc. On the other hands, rendering performance will be relying on whether the whole page is being rendered or an active area of the whole page is being rendered.
I like to hear more about the tool and understand it better.