I regularly check in or click on a link from a thread update email and It is quite an enjoyable browsing experience. Other forums are far far worse. It seems that phpBB have done a good job in this case. I'm browsing on a Blackberry 8320 with the latest firmware (cursor bassed and zoomable browser).
i check it now and then on my iPhone, which is acceptable, most anoying part is the speed but that is the network and not the RB site.
I have to say it is not save while driving the car,..crashed it almost 2 weeks ago because i was checking an PM from Luke,..had to see what colour the Boulder was going to be