Rogers has decent coverage in south central Ontario, but that's pretty much it. In most of the country, if you are not right in the metro area of a major centre, you get no signal whatsoever with Rogers. A five minute drive outside of Winnipeg, and you've got nothing. Driving through Saskatchewan, nothing. Large parts of Alberta, nothing.Virtually all of BC, nothing.
I found this out the hard way in October. Our CDMA phones had 4 bars, the GSM phones had no signal, almost everywhere between Winnipeg and Smithers, BC.
I travel frequently across Canada cost to cost and found the coverage far better on Rogers network than when I was with Telus and Bell. The reality is that each carrier may have coverage in an area remote that another carrier does not. Example when I travel from Vancouver to Calgary I have great coverage even along HWY 5. I recall stopping to assist at 4 car accidents during heavy snowfall through the Rockies last winter where people were surprised to see that I had reception on my Rogers phone but they didn't on their Telus and Bell cellphones. Also keep in mind it's not just the network that's an issue with reception but also the phone itself. Traveling with others on the East coast I noticed that friends/family using Nokia and Samsung phones had some crappy reception issues but I didn't when I used a Sony Ericsson W810 and later with a Blackberry 8100 Pearl. Since buying an iPhone and unlocking it to use on Rogers network I've noticed this smartphone far surpases any of the previous cellphones I've used on any carrier. It also worked beautifully in the USA while on both AT&T network and T-Mobile Network. This proves that not all cellphone are alike and that each manufacturer tests their hardware differently. I know it can be frustrating to lose coverage when you need it but like I said the reality is none of the carriers provide 100% coverage across the entire country.