Apn config is a work in progress.
Obviously works for some and not for others, but O2 in UK comes up frequently in mobile forums as a pita to connect to.

Remember this is still a testing (beta for want of a better word) image. team is working hard to bring us a good product.
also things like apn for mobile data were not in the original scope for DE and have only recently been added.
things like ringer profiles and sms/calendar event alerting are of lower priority than things that break the ux.....