In practice, when I'm thinking about an opportunity cost to get points, I'm only using one valuation: the redemption of the points for a nice domestic US property. When I think "How much 'rebate value' does SPG Amex yield on purchases?" this is what I'm thinking of.

Internationally, the reality is that I typically forget about Priceline because I don't usually want what they have to offer, and forget about awards because the rates are either too high for my tastes or the awards are unavailable. I kind of like the small boutique hotels in Europe better than the American chains anyway, so it's not as big of an issue for me.

Perhaps my opinion would be different if I were top-tier and KNEW that I was going to get a big upgrade to a suite. I'm Gold in MR, HH, and SPG. I doubt those levels would earn huge upgrades on award stays at any premium property. So I'm not building a lot of "value" into the award based on upgrade chances.

I probably should have pointed out in my first post that my opinions and calculations are very much driven by the two credit cards (SPG and HH Amex), not the hotels themselves. These days, the cards are my biggest source of points, not stays. I understand your perspective - HH Diamond is a very good place to be from the perspective of earning a lot of points AND being able to redeem them without hassle.