Don't know why people are saying Firefox is fast, Speedometer 2.0 shows a score of 47 where Chrome is 67 on my MBP. And on my PC, Chrome gets 76 whereas Firefox gets 64.
Besides, there are some things benchmarks don't check. Examples:
Chrome startup takes at least 3 on my machine. It's does heavy disk activity during this period. Firefox on the other hand takes at most 30 seconds.
Ram usage is also way higher on chrome than Firefox.