I'm sure that many of you who are researching this area are also looking at Rancho. I'm not going to get into the details of the roads up the hills and whatnot as that is fully covered. My wife and I stayed at both Oxy and RP last Feb. They are different. Overall, Oxy is more laid back and more hip in my opinion. RP is more refined and stylish. We stayed in one of the least expensive rooms at RP and while it was nice (great bathroom) it was a bit of a letdown from our room at Oxy. While everyone at RP (owners, staff, guests) were very nice, it just felt a little pretentious at times. Most guests here are staying at very expensive villas (very nice if you can swing it) and, at least while we were there, these guests seemed to all be members of a club we were merely visiting. That may sound weird but it's the only way I can describe it.
If we were to return, I'd pick Oxy over RP. It is not only a better value, it just feels better. The food at RP gets a slight edge (breakfast is great at RP and included) and the service at RP is slicker, Oxy just feels better.
One last difference, the staff at Oxy is pretty transparent. I mean this in a good way. Very accommodating and then they leave you alone. That's the way we like it. If you need people fawning all over you all the time then RP might be a better choice.