I would bet on Schneider being better long term.
Dubnyk was very good the last 30 games or so last season and has been outstanding so far this season but other than that, Schneider has been a lot better at every level and has more raw ability. If Vancouver was crazy enough to offer Schneider for Dubnyk straight up, i wouldn't think twice about pulling the trigger on that deal.
It's tough for Dubnyk to go a whole game without ONE bad goal. Plays good majority of the game and then lets in a stinker at the wrong time. If this stops, then it gets close, but for now it's Schneider considerably.