I've tried it. It works, but it isn't great. Opera is slightly better than the built in browser. When it comes to websites like this one, screen size is the issue, so it is no worse than any other similar sized device. In common with other sites, PPRuNe's page design doesn't lend itself to these devices, because the column down the left hand side with the posters name takes up all the space.
Overall I don't like the phone and have now replaced it. The hardware is pretty good, especially the little keyboard, the battery life etc and it's fast enough. However the Symbian UIQ software is not good enough - the user interface is really poor, especially if you prefer to operate it without using the stylus.