From an architectural stand point, it is not even close.
oh please. is this really necessary?
first, it's not only about architecture per se, but let's ignore Van Cortlandt's historical significance and the fact that it's playing as nicely as it is (the guys that were running Forest Park now run it, while Split Rock is held by American Golf), or that VC is just much, much easier to get to on the subway. Split Rock is a beautiful old Westchester-style course with big trees and little domelike greens. there's a greater variety of holes but the succession of longish slight tree-lined doglegs is kind of monotonous. okay, the greens are better. but there nothing at all inspired about the bunkering, and the collection ponds on the back are sumplike.
I used to quit playing Van Cortlandt after 14 because the walk is such a nuisance, which is still a nice quick round and a half. but first of all, the fact that most of the course surrounds urban wetlands, and that it managed to survive all the challenges it's faced in its 113 years, including Robert Moses and The Three Stooges, gives it practically geological significance. the meadowland loops -- try to imagine where the 700-yard ninth was laid out -- yield a succession of pretty and quite entertaining holes, including the 6th and 7th, two quite engaging short par-4s.
for challenge? Split Rock by a mile. in terms of historical architectural interest, yeah, that really isn't close. VC's delicacy and history (Babe Ruth, John McGraw, W.C. Fields) and remarkable urban setting trumps whatever relatively superior strategic interest SR has.
but -- it's a matter of personal preference & I love them both. and once again the fact that Split Rock can't be gotten to easily by public transportation makes it the course I'd recommend someone traveling with his clubs out for a round.
if I'm in town I'd certainly be up for a visit. they're all easy on the wallet, too.