We all win, because even if Chrome is the slowest, it's not slow.
Two things this Lifehacker article did not cover that are important to me: creating new windows and creating new tabs. I do a lot of this. I haven't timed it but if I had to take a guess I'd say Firefox is at least twice as slow as Chrome at making a new window. I think that explains why Chrome feels faster to me.
(OS X 10.6.8, Firefox 7, whatever latest stable Chrome is, in case anyone's wondering.)
Who cares if browser startup takes 3 or 6 seconds? I start my browser in the morning, and never close it.
And who really cares if some browser eats 50% more RAM? RAM is ridiculously cheap, 8GB of laptop memory with the highest reviews on newegg is $40.
So more precisely, Chrome is fastest by a huge margin on the benchmark they explicitly tuned for.
Also, Chrome is the fastest in V8 by a huge margin, while similar or a tiny bit slower in other benchmarks like Kraken or SunSpider
There are plenty of real-world JS applications where Chrome (well, V8) is much slower than competing browsers. Just browse through V8's bug tracker. For example, here is one I filed,
http://code.google.com/p/v8/issues/detail?id=1630
And I am sure there are even more such issues on the internal (non-public) issue trackers.
Different JS engines tune for different things, we can no longer say that any one of them is simply "faster" than all the rest. It depends on the benchmark.
In terms of real-world scripting, almost any script I've benchmarked has always been ~1.5-2 times faster in Chrome than firefox (versions 4 through 6), except when bound by API calls (last I checked Firefox was on-par or better when dealing with TypedArrays). It looks like TypeInference might be a really big win though.
The last one I tried was 5x slower in Chrome than in Firefox... Sadly, it's not a publicly available url.