I like Kam snaps for the wide variety of colours available! My supplier is Green Beans in Brisbane and available online. Their special pliers make attaching snaps easy - see my short video here.
I've noticed a couple of local sewing stores offering the use of their snap setting tools when you purchase just a few sets of these snaps for small projects, so ask around!
Of course, these fastenings can also be replaced by good old fashioned sew-on snaps, or buttons and buttonholes, but I prefer the way Kam snaps make your playsuit fully reversible!