He's repping a flush or A4, and we expect him to play his sets faster on the whole, so I would fold even getting 3-1.

We should expect a micro player to be bluffing the 25% required to make the call, even taking into account that he might have played a smaller set slow.

river is not a value bet btw

I would bet bigger on flop and especially on the turn I might even overbet versus a calling station, but no bet for me on that river, everything came home to roost.
I'd most likely check and call a smallish bet, but if our opponent got too busy with their chips I'd fold.