I feel there is still plenty of scope for a commercial RISC OS browser, but it has to offer:-
* Close to or better than FireFox's level of compliance with typical sites
* Plugin components such as Flash
* Better speed and responsiveness
* Better integration with RISC OS (file saving, launching PDF readers etc)
* Better quality of display
On the latter point O2 produces some of the most pleasing displays, as I have to say its TTF render lookes better than RISC OS font manager a lot of the time, especially when using TTF fonts that sites have specified in their design, such as Verdana on news.bbc.co.uk.