Micro-benchmarks?

We have had Word Processors and Spreadsheets in Javascript (Google Docs), 3D and 2D games, and even a h264 decoder and a PDF renderer. Heck, they have ported QT to Javascript, and the example applications run at a very acceptable speed. None of the above are slow.

So, no, it's not true that V8 is only fast in selected "microbenchmarks".

You might not do scientific applications or NLE video editing with it, but for everything else it should be just fine.