It's a step in the right direction and one of a number of updates that the firefox dev's seem to be making in the last couple months to catch up.

Yup, it would have been nice if they were on par with webkit a long time ago, but it's still an improvement and one to be excited about. One less thing that "only" webkit can do. This makes my job easier, especially when the client wants/needs cross browser support.

I wouldn't be to excited or proud about being "ABLE" to only work for Safari. You are shoe-boxing yourself, and as nice as it may be to have such a singular focus it's not so good; if at a later date you are ever forced to work outside the confines of your space.

Until webkit becomes the only rendering standard it behooves the web developer to be as versatile as possible within the web space to maximize their potential.