What is the advantage of firefox 4.0 over origin web browser?
OWB is, at the time, certainly faster than Timberwolf. If you are content with OWB, there isn't much point to switch over now.
However, Timberwolf/Firefox is a more complete browser than anything else on the Amiga so far. It can use all the add-ons from the PC/Linux/MAC version (minus those that require specific platform support). AdBlock is one that I use, but also things like Web Developer Toolbar are very useful.
Also, Mozilla offers a technology, not only a web browser. Other programs like Thunderbird (E-Mail), Songbird (Media Player), And Sunbird (now Calender for Thunderbird, a calender/reminder) use the same tech.
Once we're finished with it, it will also have things like WebM (HTML5 video) replay (it can do that now but slow), WebGL, and a few other nifty features.
~~ Rogue
