Version 2.0 is intended to be an improved version of Firefox 1.5, rather than breaking new ground, according to Ben Goodger, Firefoxs lead engineer.
In addition, this is not a feature-set release. According to the Firefox 2.0 roadmap, this is a pre-feature alpha release. As such, youre not going to find such expected features as improved anti-phishing, session-restore or remote extension management. It is, in short, a pre-release meant only for developers who are working on the programs basic internal functionality.
From a Web developers viewpoint, the goal of Version 2.0 is that its APIs (application programming interfaces) will be compatible with 1.5s APIs. Thats not to say that new APIs are being ruled out, but existing APIs are very likely to stay in place.
According to the latest Firefox 2 status meeting minutes, the "[user interface] is known to be annoying, but [the] internals seem solid enough for a developer preview." According to these minutes, it would seem that the real alpha release will be this coming Friday, March 24.
Users who want to try it anyway can count on seeing broken extensions and other problems. For example, in kicking the tires of this pre-alpha release we found several pages that display properly under Firefox 1.5, which failed to appear correctly under 2.0.