Very good summary.
I moved out from Aeroplan to RBC Avion (similar to CIBC Aventura) several years back. Plus also have Amex. You are correct that it takes longer to accumulate Aventura points however it is way easier to redeem as you can pretty much book anything. The main point for me is availability (multiple tickets) specially around March break, Christmas etc. Its difficult to get Aeroplan availability unless you book well in advance and even then there may not be enough seats or a convoluted routing.
I have redeemed Amex points, RBC points and Aeroplan this year.
For long haul J, Aeroplan is a better option.