Concierge.com's insider take:

Given that Ventana sits right across Highway 1 from Post Ranch Inn, it's hard not to compare the two—and though they're equally wonderful, they're also quite different. Here the architecture is chunkier—decidedly high-end '70s—and rather than being tucked away among the trees and cliffs, the buildings sit on wide-open, rolling grounds (which means more expansive vistas, and also that you'll see more strolling guests than you will at the ultraprivate Post Ranch). Ventana sits higher up, so the fog clears sooner, making it better for sunbathing; the spa here is also larger, although it's also open to nonguests. There are hiking trails that crisscross the property, yoga, and "photo safaris" with the resident photographer—but there are also hammocks where you can lollygag all day. The 60 guest rooms are bigger, and the furnishings made with leather, redwood, and rough-hewn cedar give them a woodsier aesthetic. Other unique Ventana amenities are the cedar-walled Japanese-style baths open to the sky, and the clothing-optional pool (there's another for those who are more modest). Kids are not allowed.