both cartridges are obscure enough that they're really not suited for one who doesn't handload. Options are limited and availability may not be reliable.
I'd suggest that unless you intend on handloading, stick with a more common cartridge so that you don't find yourself in a case where you can't get ammo, or can't get ammo that works well in your gun
FWIW Al Simmons in Hamilton ON has/had 17 Remington.