Seems that the difficulty has changed over the last year on some courses. They are all playing really tough for me now, but with the nastiest pin placements and heavy winds they rank (toughest first):
1. Oakmont (because of the height variations and impossible greens)
2. Royal St. George (crazy inconsistency in ball distance and some green terrain reads that are wildly misleading)
3. Congressional (seems like all mistakes are exaggerated by the kindly folks at WGT and the bunkers have vacuum action)
4. Bethpage Black (although heavier winds actually make some of the holes more playable than in low winds)
5. St. Andrews (seems to be tougher than the original version, although there are a couple holes where I've hit 3 different irons exactly right under the same conditions that end up in the same place as if predetermined)
6. Kiawah (playing a tad tougher lately, but I always enjoy this course)
The last several weeks have been a real slog. More frustrating than fun. Heavy internet traffic in the mid fall through the holidays makes for very stuttery and inconsistent meter speeds and the courses WGT are putting up for free weekly tourneys are set up so tough it is hard to score. I want the game to play to my fantasies, not to mirror my struggles on the real courses I play.