I work for a Telco. so I won't get into brands or preferred carriers because someone may think I'm biased. The only advice I will give you is to not sacrifice coverage just to get a specific model. Missing out on a feature on the hottest new phone is one thing but being totally disconnected from all the features because you are in a poorly service area is another. Nothing is more frustrating.
If you worked for MTS (Manitoba Telecom) we would be having words.
Our MTS based iPhone barely had good coverage in downtown Mississauga which is outright sad.
Telus (not based out of Manitoba) has better coverage for cells in northern Manitoba than MTS!!
I know because our old work cell (MTS) was junk in the field while a colleague had his Telus cell phone receiving signals constantly in most locations.
