CB is probably a little better than Brora, but not much. Both can be a lot of fun, in their own ways. I don't think the extra 4-5 hours drive time is worth going to Cruden Bay, but I'm a minority on this site. Here are the pros and cons:
Cruden Bay: longer, more spectacular holes, larger greens, no cows or sheep, weak start, great middle, weak finish, on the beaten track, great views from clubhouse, many chances of losing golf balls
Brora: off the beaten track, sheep and cows, greater design integrity, smaller harder greens, better collection of par 3s, othe holes steady rather than spectacular, zero chance of losing a golf ball, great views from clubhouse
Whichever you choose, you won't go wrong.
Enjoy