Matt Judy defends the development of Chimera for Mac OS X as good for the Mozilla project. I believe he’s right. The more browsers that are using the underlying Gecko engine on various platforms, the better the code will become. As long as the Mozilla derivatives just swap out the UI but keep the Gecko engine it still helps to build a better and more standardized web. My only concern is that these new browsers will be perceived as separate entities with small marketshare and therefore dismissed by web developers.