except when I do that I get unresponsive script at "date-format-tofte" so I had to actually disable it to complete the test.
there is no question tracemonkey is buggy and in bug fix process as of now, and the problem sometime won't even repeat itself.
Update, there said to be a bug that has been fixed, try run sunspider again with today's build.
but I do know tracemonkey is going into firefox 3.1.
Here are some result provided by developer, run against sunspider

when you look at V8's sunspider, it obviously runs super fast on some items, and ridiculously slow on others, I think google did massive targetted optimization, Im not even sure if those optimization can be easily transfered onto linux or osx, thats why I think osx or linux version won't be out at least for another 3 month.

Mozilla said the ones that TM is behind are under work already and they have a plan that can do even better than V8, I guess we just have to wait and see.