MDF takes paint well. I like shellac best for sealing the edges of MDF -- Bull's Eye straight out of the can is fine for edge sealing, although I would cut it at least 50% as a finish.

Since you are not going to spray, you can use a primer like Zinnser's. It comes in three flavors -- shellac, oil and water based. I prefer the shellac base because it dries fastest and sands best. Once you build up the primer base, you will have to sand down to at least 400 grit to get a smooth, mark free finish. and the 400 grid sanding needs to be wet, so make sure you don't go through the primer to the raw MDF.

You MAY be able to get a smooth brush stroke free finish with an oil based paint. You will probably have to wet sand out the brush marks and then spray on a polyurethane or acrylic clear coat.

A quality paint finish is a lot of work. This is why I don't advertise a paint finish and strongly discourage it to those without proper spray equipment.

Got any friends with spray equipment?

Bob