JS loading is slow in FF, but the real killer is anything DOM related. On large pages this is measured in seconds not milliseconds. The worst part is that it scales non-linearly with # of DOM nodes on the page, # of DOM nodes loaded in other tabs in FF, how long it's been running and who knows what else.
The longer FF works on improvements on benchmarks on which it is already fast, the more market share Chrome will take by making fast things that actually matter.
I agree 100% and have been complaining about exactly this for a long time (e.g. http://news.ycombinator.com/item?id=325742). The fact that IE is the whipping-boy of the web community has caused Firefox to get more of a free ride than it deserves. That will eventually change.
It does appear fast, but I'm withholding judgement. I'm not certain if it's doing caching tricks or whether their parser really is 10x faster. It certainly is CPU-bound, which is as good as it gets, and it's more stable in terms of memory use.
Animation in FF 3.6 is noticeably smoother, apparently due to the improvements in GC. In other words, it may not have improved much in the specific areas these benchmarks measure, but it's important not to take that to mean that the JS engine didn't improve.
The longer FF works on improvements on benchmarks on which it is already fast, the more market share Chrome will take by making fast things that actually matter.