is it better going for pre primed mdf skirting boards or normal pine ones, ?, obviously the pre primed ones will mean no undercoarting, but just wondering wheather i will noticed the difference when its all done?
If they are going to be painted, I would go for MDF against real wood, no knot problems, as you say no need to prime.
I primed mine though. I fitted using glue & screw, then filled screw holes, rub down, (gently) then gave a prime, followed by one coat good gloss. Im happy with the finish, although I only look close when Ive had the extra beer.