Most recently, both Firefox (here) and Opera (here) have been featured in Slashdot posts mentioning how great their latest bleeding edge development versions are. So I figured I'd give them all a whirl. The results are here.
For this comparison I used nightly builds of Firefox and Webkit from 12/22/2009, which is the date the Opera 10.5 pre-Alpha was released. Unfortunately I could not go back in time and grab the latest Chrome development release from that date. So its possible that Chrome has a slight advantage in this comparison.
In the chart, a red box indicates that browser's score was worst or tied for worst. A green box indicates that browser's score was best or tied for best. Some comments on the results:
1. Firefox does a few things well, but overall lags far behind the other options. It turned in the worst overall score in Sunspider, V8 and Dromaeo, all by a significant margin. All four were roughly tied in Peacekeeper. More on that later, though.
4. Opera is doing something fishy with regexps on Dromaeo. Most likely caching results. Its score is an order of magnitude higher than the other browsers on that particular test, while being only moderately faster on the others.
6. Every browser had at least one area where it was the "worst" among the four options, and each browser had at least one area where it was the "best". This suggests there is at least some low hanging fruit left for each of them to pick, though less so for Opera.
7. All tests were performed on a 1.8ghz Pentium-M running Windows XP SP3 with 1GB RAM and Intel integrated graphics. This processor has SSE2 instructions, so Opera's performance shouldn't be negatively impacted.