One thing that must be considered, is that no Canadian type certificate exists as yet for either ERJ.
This is a significant hurdle that the first Canadian operator must jump.
It will include a complete review of the design to the latest standards for an airplane that was designed and certified to standards several years old. (Airplane TCs certification basis is locked on the date of APPLICATION)
This means alot of paperwork and a cold soak qualification test. And probably several modifications to turn it into the "Canadian configuration".
On top of all that, I've inspected both close up and in my opinion, the ERJ series is junk compared to the CRJ. The construction and design quality fall behind the CRJ. For that reason alone, I hope AC doesn't put all its berries in the ERJ basket.