Played Fraserburgh and Peterhead, but not Murcar.
I'd rate Fraserburgh a notch above Peterhead. It's more consistently good throughout, and although 1 and 18 are dull, the opening trio at Peterhead is arguably duller, and the front nine at Peterhead is fairly weak, with only 9 being a truly above-average hole. Fraserburgh gets going at No. 2, and features consistently good links -- nothing I'd call truly great, but little that is average, either, until you come off Corbie Hill and return to the flat meadow of 18. A short course -- it tips out at 6,300 yards -- but its small greens and exacting demands on approach shots provide some character and a good test of the game.
Having said that, I really enjoyed Peterhead's back nine -- a very good and very linksy nine amid the high dunes.
A hidden little course with a great history nearby is Inverallochy, a true out-and-back links that is not in the league of either Fraserburgh or Peterhead, but nonetheless has some good holes. There is also a fairly rudimentary nine-hole links course at Rosehearty in the same area.