Gotta question the presence of Chicago Golf Club on this list. A low handicapper would only have trouble with that golf course if he was putting horribly and the greens were Stimped around 15. That's not to say it isn't a good golf course. And it is not to say that it isn't interesting, or demanding for that matter, but resistance to par is not something that applies to CGC.
As for Butler/Medinah, they are both extremely tough for good players. Medinah is a brutal slog of a golf course from the back tees, with a lot of 480 yard par 4's uphill with narrow fairways and severely tilted greens, not to mention a very difficult collection of par 3 holes over water. Butler presents some similar challenges, but it has the added feature of the difficulty of getting the ball onto its greens that Medinah doesn't generally have. At Medinah, generally speaking, the greens are right in front of the player, with not much of an angle created by the orientation of the green to the fairway. At Butler, the angle of attack to virtually every green is extremely shallow, with big difficulty around more than one side of the green (i.e. a creek or some woods or a pond). Both courses are long and both courses can present some problems with respect to the ability of the player to hit the fairway, but access to the putting surface at Butler is as difficult as any golf course I've ever played.