I think size can be both a blessing and a curse though as changes are harder to implement on a large scale and sometimes their suppliers may not be able to give them the kind of connectivity they need.
See how they have only just recently increased their handover circuits from multiple gig links to 10gig ones, I'm fairly confident that they were waiting on their layer 1 provider for this as they've had their ERX's and big juniper M series routers for some time now.
It is interesting though that they have changed their traffic management policies a number of times over the last few years to try keep up with what users are doing, having various customer segments would make this overly complicated.
I don't follow Orcon very much but from what I've seen most users are happy with their service and get good speeds? not?
Is your main issue that there seems to be some sort of inequality between users of the same class service or that some applications / sites are managed to a point where its unusable?
nice little NZ ISP comparison to see whether you've got an unrealistic expectation :) , results will be better with more participation!
Finally can anyone else confirm if what Aaroona said is true?