Best answer by BobTheElectrician
Keep your Koodo account active. Get your phone unlocked (iPhone very expensive to get unlocked with new suppliers) if you are going to switch.
The same situation works both ways, going to Koodo from anyone else.
If you can afford the upfront cost, buy an unlocked phone. Long term phone cost + plan cost = real cost of service. You must do that calculation yourself.
Koodo may be a better bet in the long term, depending on your usage.