Manji said:
Is there a big delay when you switch? Obviously I want the transition to be quick and smooth....
Should I cancel with Telus first or should I cancel with Telus after I sign the contract?
You don't need to do any cancelling. The new service provider will give you a new phone with a temporary number, then they will port your number over for you. You'll receive a text message informing you that the port has completed.
I believe that they claim the port can take up to 48 hours, but I do this all the time at work between Bell and Rogers and it never takes more than a few hours.
Keep in mind though that if you are still in a contract, you will incur a cancellation penalty.