What carrier should I go with for my Iphone in Canada?

I have an unlocked Iphone 4 so I can go with essentially any carrier - WIND seems to have the cheapest plans but are they good? Telus and Virgin Mobile have ridiculous prices so they are out. I was trying to decide between:
WIND
Rogers
Fido
Koodo
Any thoughts?

Wind has good rates, but these apply only within their coverage areas, which are quite small compared to the other carriers. Outside these areas (most of the larger cities), you have to pay roaming rates, which can add up quickly.

Rogers and Fido are the same company with slightly different pricing (Fido is usually a bit cheaper).

Koodo is part of Telus but has less expensive plans. They share towers with Bell. Koodo/Telus/Bell coverage is good in most places except Manitoba, because in that province MTS has an arrangement with Rogers and not Bell/Telus.

You'll have to decide what combination of features suits you best.