I grew up at Piping Rock and to my knowledge Piping is basically Raynor's first real solo design (1913). Macdonald is given attribution (with Raynor) but the fact, as I understand it, is C.B got extremely pissed at Piping for not allowing him to utilize the ground that was the polo field (the present absolutely enormous practice field).
C.B was a tough and intransigent man, I'm told, but the high style, world class polo interests on Long Island at that time, and very much including Piping Rock Polo, was tougher and more intransigent than C.B. He lost the battle for those polo fields for golf (which he insisted on) and quit the project at that point which was befoe the golf course was constructed.
Piping Rock is a wonderful golf course and has been lenghtened in the last twenty five years to make it a better test for the bigger hitters of today, but it's a bit more formal and traditional, dare I say, normal golf course than the team of MacDonald/Raynor's best!
Piping has a great Redan and one of the few that's green site seems actually higher than the tee which I feel makes for a really good redan (in the etymological sense of a fortress). As much as I love Piping's Redan, certainly in the top 3-4 in the world, it still is overshadowed by NGLA's #4. Piping has a great Biarritz though.
Piping's "Road Hole" is somewhat of a mutt! It was originally designed as about a 350yd par four and the green design is about suited for that (maybe add 40 yds max for today's big hitters), but it isn't the proper proportion or the ideal orientation for the tee length they added to it.
Piping Rock is a great golf course and the "usual suspect" MacD/Raynor holes there are good ones. #13 is a straight away short par 4 that due to its green and green site is in a class of its own, but the "short" is also a total mutt and really should no longer be identified as a MacD/Raynor "short". #16 is a good strategic hole tee to green and #18 is fun as a finisher to try to figure out exactly how to make birdie, if you need it!
But for sheer architectural brilliance and architectural guts Piping never touched NGLA and it never will!