I am using the fennec 4 beta since beta 1 and I'm upgrading it every few days to the latest nightly build. Its really fast to use already, and scrolling seems even smoother than with microb. Its also using slightly less memory (quite incredible) and I'm not even counting the mem usage of the browserd daemon that's always running. Start-up time is ok, though not quite as fast as microB (and I doubt that it will ever be as fast as microb as it has its browserd daemon running all the time). But on the other hand I observed that while microb starts really fast, it takes a long time until it loads the first site, so I think that it still has to load its browsing engine. Therefore I think it doesn't really take any longer to display the first site on fennec even if the GUI starts up slower. There are still some shortcomings though: -There's no possibility to enable the mouse pointer you can activate to select text. -Flash (should be fine later on though) -not all plugins are working right now -the chat panel in facebook (and similar panels on few other sites) aren't staying on the bottom of the screen when scrolling I still prefer to use fennec instead of microb, except for some sites like facebook or when I need to copy some text, etc...