9:52 pm
tri-band of 900/1800/1900
Yes--but. The North American GSM networks operate on two bands, 850 and 1900 Mhz. (Elsewhere 900 and 1800 are used.) Coverage does not fully overlap so a phone that has only the 1900 band may not work everywhere in Canada where there is GSM coverage.
I have no idea these days how limiting that would be.
11:33 pm
To me one of the most important things about a cellphone is how good the reception is.
With a 900/1800/1900 cellphone, you're only getting reception from the 1900 MHz towers. Rogers (the towers SO uses) has probably covered Canada assuming that their clients are using phones with both 850 and 1900 MHz.
So, you can use a phone with only 1900MHz (I think most of the older Fido phones were like that) but your reception may suffer.