Octane is Google's own benchmark suite. I don't think getting beaten on your own hand-picked set of performance metrics satisfies any definition of "impressive".
It sure is far better than idiotic SunSpider. They are close to real-life application examples. If they really wanted to hand-pick they would not include asm.js benchmarks, where Firefox has a certain advantage.
The notable thing about this achievement is that for a very long time V8 was miles ahead of the competition on its own benchmark (first V8bench, and now Octane), as the graphs at http://arewefastyet.com/ show.
