I would recommend this for anybody who is just getting started with rspec and rails. As its title suggests, it covers the basics: a bit of BDD philosophy, getting things set up, writing simple examples, all the way through describing models.
As for advanced users, I’d recommend this to those of you who are interested in a few helpful tips and tricks. There is some material on the textmate bundles and integrating with growl. In fact, the approach to validating models is simple and pragmatic, and one that I suspect will become the standard in time.
The only constructive criticism I’d offer is that the discussion of the philosophy of the rspec team doesn’t recognize the roots of our philosophy in Test Driven Development. It seems to present writing focused examples, getting them to fail first, etc, as our idea. It is not. Just ask google.
Regardless, it is very exciting to see the beginnings of quality educational material on rspec and BDD emerging. Keep your eyes open in this space. I suspect there is quite a bit more on the horizon.