I bought both Gordon’s HU course and his 6max course (from bestpokercoaching.com). I play anything from 100nl to 600nl. The 6max course is decent, but the HU course is just great. It teaches a drastically different style, in comparison to other courses, but it actually works a lot better.
So after finishing the course, I took some private HU coaching. All I can is that Gordon’s coaching is worth its money instantly, by like a threefold or so. The only annoying thing was his German accent, but I can live with that – as long as he’s making me so much money