for what it's worth (who am i after all...) i agree with andy.
i think 50 cal is going to come from the new fields, or fields replacing gear, upwards.
reason: more profit.
after all if the balls are significantly cheaper wholesale, then the field can continue to charge the same "cost per ball" as before. after all, the majority of fields serve the stag do, birthday party, office group, etc who play once in a blue moon and can expect to pay a premium price. they don't know the differnece between 50 and 68 cal. all they know is they point and shoot. and it makes no difference to them either - as long as the paint flies straight enough and doesn't bounce like buggery.
when/if it creeps into the hands of more serious players it'll be because it has shown it does what it says on the tin.
rec players, like myself, are likely to pick it up if it has that better accuracy at longer ranges it claims, as well as the fact that we can carry more shots in the same space and get more shots per fill. but it will need to prove itself before i go there.
tourney players. i guess the thought of less reloading or smaller hoppers is appealing. the reduction in cost for the volume of paint would be beneficial. but i can see it being harder to ref games with smaller paint marks....
we shall see. give it a chance and we might all be pleasantly surprised.
i am of course with several others on this. i don't want to go buy a whole new expensive shiny toy, just to find it doesn't take off. i like my markers that i have now. if a drop in kit comes along at a sensible price, then i may well give it a shot.