honestly maybe ds2 with K&M is better for multiplayer, I cant know until I try it. I tend to play singleplayer games with controller unless they require aiming or mousework.
but I will defend my saying that owning a controller even as a PC gamer is an essential. so you can play certain games reclining on your couch/bed, there will always be some games better suited to controller without debating which you surely agree that that is true. when occulus rift comes out, you will want a controller anyway.
plus "£40" for controller, are you high? the official M$ ones are 20 squid, pretty sure I got mine yonks ago for 15.