Closing thoughts
Overall, I have been happy with both Opera and Firefox. Both are rich in features, and though only Firefox is open source, both browsers offer many options for customization beyond mere cosmetics. I cannot say that one browser is superior to the other. If one is willing to consider both open and closed source options, than picking one of these browsers over the other will likely come down to issues of convenience, personal preference, or the particular tasks one typically uses his browser for. One user may choose Opera for its one-time install with no assembly required, while another may choose Firefox because of a handful of extensions he simply cannot do without. Perhaps Opera's integrated mail and chat clients or method of RSS implementation will win over one user, while another will gravitate towards Firefox's lack of banner ads and choose Mozilla's Thunderbird for email.
