Pine and softwood skirting boards may give you a little more leeway when fitting skirting. Also you have the option of planing the skirting, before fitting whereas MDF will not take so well to planing it DIY!
Pine skirting also offers you a cost effective decoration line if you’re going for the less expensive options for example a buy to let property or the ‘spare room’ !
Those of you with a an affinity to all things old and antique, then antique skirting is just the thing to make your home look oldy-worldy and give it a sense of tradition …