RE: should I get the 257 Roberts?
It's certainly a great round, I don't have any experience with the 722, although the older remingtons were of much better quality than they're putting out now.
I'd go for it, there's absolutely nothing wrong with the .257Rob, as long as you're satisfied with the selection of available ammo near you, I'd get it.
(Around here, there aren't many shops that carry more than one or two loads for it, and most of the shops all carry the same one, so there are basically three bullet types/makes available around here, if you're looking for more, you've got to order them specially or get a more locally popular round. The .257Rob seems to be very popular in certain areas, but sparsely used in others, which is sad since it's such a great round.)