Bee: I know what Ive seen - Ive changed ISPs a few times in the last few years, most promise connection in 5 or 10 days and deliver pretty much on Schedule. Telecom promised connection within 48 hours and delivered well under that - for me and for one of my friends also...
YMMV for sure but you will take a lot to convince me that my personal experience was just luck and not the result of some special relationship between chorus and Telecom :)
Changing ISP's and requesting a new connection at a new property are two entirely different processes.
If you're merely changing ISP's it's pretty much the norm for that to be able to occur within 24 hours regardless of the ISP. It simply requires the VLAN config and tunnels in the ISAM to be changed.
If you have evidence to suggest Telecom are favoured I suggest you ring the Commerce Commission, they'll be very happy to speak to you!