Idk really
I just came off a contract with Rogers (who I hated) and traded to Bell (after much searching)..I now hate Bell.
On the plus side I have argued my bill every month for the last 6 months and easily got lots of the extra charges reversed..so far.

Rogers (and their owned subsidiary Fido) has the advantage that they use GSM, so you can easily buy new unlocked handsets when yours breaks.

If you can hold off, there's going to be a whole slew of new cell companies starting in November I think as the market gets opened up.

I noticed I pay way more on my canadian plan than my US buddies (by about 30%) so it may be worth it to keep your US plan and tack on a Use in Canada option?? check it out

good luck and if you need cdn questions answering ask away

Mal.