Superbird is a browser based on Chrome, which the authors say places special emphasis "on speed, stability and data security".
The most substantial difference appears to be on the privacy side, as Superbird comes set up to send less data to Google. So it won't generate and transmit a client ID after installation, for instance. It won't send any data if the browser crashes, either. Superbird doesn't install an updater, either, so it's not looking for upgrades in the background, and it won't send information to Google as you type addresses (although this can be a down side as it means the browser can't suggest URLs).
The authors also claim Superbird is almost 10% faster than Chrome, although it's not clear how they tested this. Our own tests show a slightly different picture, with Superbird taking only a 3.5% lead in the Peacemaker benchmark, while it actually lagged Chrome by around 5% in SunSpider.
Otherwise, though, Superbird is more-or-less what you'd expect from this kind of project: it looks and feels like Chrome, more or less, but is just a little simpler (there are only 11 extensions available as we write, for instance).
Is it worth installing, then? Probably not, as you can turn off most of Chrome's communications with Google anyway just by tweaking its settings. But if you'd like even more privacy then it might be worth a try, especially as we're linking to the portable version, so there are no adware or other complications here: just unzip and it's ready to go.