Multiprocess Firefox
My biggest problem with Firefox is its startup time. It takes much longer to start the firefox.exe then IE and Chrome which are both very fast.
I am using Win7 on i7-3960X, intel SSD, 16 GB RAM.
If I install any plugin then this thing is much worst. (For this reason I am not using any plugin which is a big loss).It is weird that this issue is seldomly mentioned, but I think that it is much more important then the other performance benchmarks such as javascript performance.