It probably doesn't matter, you should be able to get summer vacation on either one quickly. The 717 is significantly easier from the FO perspective, and is overall a much nicer plane. I would take NYC 717 over 88. If you prefer ewr then definitely the 717, we currently have a pretty strong presence there and most commuters try to avoid it. You'd be able to snag some pretty good trips just because lots of guys above you tend to avoid it.