rainbow-davie

you have to look into each company.

not just the price, but the terms (do you have to get hosting in order to have domain discount,..etc)  

and also, for some cases I know, ppl are easy to register but hard to get any service or hard to get cancel the service.

I've registered and help other to register over 100 domains.  I recommend these two local companies:

namespro.ca
doteasy.com