I think Formby is more fun over multiple rounds but I think Birkdale is a much better sorted course in all details and forms a more coherent design aesthetic.
Brent - curious statement...care to elaborate?
Ciao
It seems to me that Royal Birkdale, which I admire greatly, has a very consistent character from hole to hole and throughout the round. It is an eminently "fair" championship style test of golf with the quirk and odd bounces we experience on many links courses pared away. It has been polished and perfected over decades of fine tuning. It is a course that will adequately sort out good play from poor play among the best players in the world but in a manner which good players tend to like and prefer.
So the "coherent design" involves large, deep, gathering bunkers but otherwise large and relatively flat fairways and greens. There is ample room off the tee and reasonably well played shots will almost always find a favorable lie. The rough can pinch in a bit depending on choice of mowing lines, especially as one gets closer to the greens. The turf is excellent which allows the course to play keenly in a breeze but is great to hit from. It's a very high quality example of the "right there in front of your" design ethic.
In contrast, there are plenty of rough edges and at least a bit of quirk at Formby. Moreover there is about as much variety among the holes and throughout the beginning, middle, end of the round as you're ever going to find at a links course. Compared to Birkdale where you feel like you've just played 18 variants on the same basic challenge, at Formby you walk away feeling you've played two or three different courses in one.
Put the best players in the world at Formby and they will not find it as eminently "fair" as Birkdale. And some of the holes would be quite weak for elite bombers, unlike Birkdale which is somewhat consistently challenging. For a double-digit handicapper on vacation however, Formby gives far more value. A good multi-round holiday trip might include a round at Birkdale along with rounds at a couple of other nearby courses for variety. Formby on the other hand has just as much to offer on the third or fourth play as it did on the first. Heck it took about three rounds before I could even remember which holes were the shorter or longer ones or recall which greens were flat and which were more contoured.