Since it's water based, how well will it be tolerated by MDF so it won't bloat?
Zinsser Primecoat is a clay-based primer - great to seal the paper-face on new, raw drywall.
MDF sucks up moisture similar to paper, so I assume it would be ok, BUT, I would NOT RECOMMEND IT.
Primecoat is just a sealer - you need two coats (it dries fast), but it is very soft and splotchy - paint will not adhere correctly to it alone. You MUST let it cure for 6-12 hours, then PRIME the surface with TWO COATS of Zinsser 123 latex Primer (2-3 hours between coats), then latex paint. That is the technique for new drywall.
However, because MDF sucks up moisture like a sponge, and then DISINTEGRATES, I would personally SEAL it using 2-3 coats of Zinsser Covercoat fast-dry ALKYD Primer (oil-based - use Mineral Spirits, turpentine or paint thinner to clean brushes; don't use the "green" stuff - it does not work and will ruin your paint or primer). Coat ALL EDGES very well! Allow to dry 6 hours between coats.
Then, you can use either an oil or latex based paint on top of this. Depending on what you are doing, if it will be used in any damp or moist area I would go with an oil-based enamel paint to give it some water-resistance. If you use oil, use Mineral Spirits to clean brushes; if you you latex paint, clean brushes with water.
If you use a latex paint, I would give it a quick latex prime (on top of the dry Covercoat sealer) with Zinsser 123, as latex paint adheres best to that (water clean).
FYI: If you use plywood, do NOT use Primecoat, ever - Use the ALKYD Covercoat to seal (6 hours dry) and then Zinsser 123 primer (2 hours dry), and then latex paint. Or, if using oil paint, just 2 coats of the Alkyd Cover coat and then oil paint.
If painting raw solid wood, sand and tack clean, and then first seal with a few THIN coats of Zinsser BIN shellac sealer. This will prevent yellow streaking and hide dark knots. It dries fast. Allow to cure 2-3 hours, then use Zinsser Covercoat Alkyd Primer, 2 coats, 6 hours drying in between. Then paint with an oil-based enamel paint OR a SOLID stain made to go over an Alkyd primer. If you want to paint with latex paint, after the Alkyd Covercoat cures, give it a coat of Zinsser 123, allow to dry 2-3 hours, then paint.
Note: latex can go on top of oil, but oil CANNOT go on top of latex!
Date published: 2016-08-17