I think the question is which pellet does your gun prefer better.
If the accuarcy level between the RWS and the Crosman are equal, then go with the locally available ones(Crosman). If however, the RWS shoot better, you might want to stick with them. After all it doesn't matter if they're available right down the street if you can't hit what you aim at consistently. Same thing with price. If you have to spend a little more for more accuarte pellets, that's better than pinching a few pennies, only to be frustrated.
Regards
Nathan