I would get whatever is cheaper. Or if you want both pleather and velour pads, get whichever one comes with those. They are the same headphone. The K271 studio, K271 mkII and K272 "HD" are all the same. AKG hasn't made a new, quality headphone in a loonngggg time.
It looks like the HD comes with velours and I'm not sure if it comes with pleather as well. The only difference between the K271 studio and mkii is that the mkii has both pleather and velour pads. they give you a different sound and comfort, so it's worth trying both.