I have never played overs/unders yet, but let me see...
They're always over/under 2.5 right? Well the Dutch league normally produces a lot of goals compared to other leagues.
From my point of view (no research or whatsoever) I would say the following.
Twente-NAC, should be an over, Twente is a good team, specially at home, scores a lot of goals. NAC also scores pretty well, but not sure if they do so away. Twente failed to win at home over Utrecht, so they will be determined to crash NAC. So I would say over.
AZ-Roda JC, should be an over as well. AZ on a 10-0 overall streak and a 12-0 home streak should demolish 16th place Roda JC with at least 3 goals behind Bram Castro.
Feyenoord-Sparta, will we finally produce a win? If so, I would say this game goes over, because if Feyenoord wins they win big. Sparta doesn't perform well either, so a Feyenoord win could be in the make. However they play so dramatically that I would not be surprised if Feyenoord won't win again. In case Sparta can compete this game will most likely be under.
Utrecht-Graafschap, two not too well scoring teams facing each other is aiming for an under I would say. Utrecht on the other hand often scores a lot at home, specially against low ranked teams like Graafschap.
Groningen-NEC, this is a tricky one. Groningen scores quite a lot, NEC not too often. I would go for under, but don't kill me if Groningen will win 3-1.