You're paying for the finish + bling + precise machining. Realistically you can't go wrong with the $30 njs dura ace cog, unless you use hubs that take campy compatible ones, e.g phil. In that case you're looking at $55 phil cogs.

Because the dura ace cogs are so cheap, there's no reason anyone should be riding anything less on a quality hub.

P.S I was going to come chat with you krusty but totally swamped with work