If you are a current Firefox user, the decision to update really is a no brainer. For Mozilla, the question is whether this major release will help it maintain and grow its web browser market share. It's a question that will be answered by more than just fancy user interfaces, that is, in the underlying technology used to render websites.firefox4-1For Mozilla, completing Firefox 4 can't come soon enough. In the last two years it has taken some hits from Apple's Safari, Google's Chrome and recently even Microsoft's Internet Explorer 9. Google in particular has gone down the route of almost constant beta updating backed up by an advertising campaign, which has seen it enjoy some market share growth at the bleeding edge.