Hilton has its own forum which is most likely where this will be moved. Or possibly the Amex forum as all 3 cards are Amex.

As a Hilton Diamond you'd get base points + any promotions you signup for and your stay qualifies for + Hilton MyWay bonus if you select it + Diamond bonus.
Best value is in the eye of the spender.
-Using the Amex Aspire you'd earn an additional 14x point per dollar spent at the aforementioned $250+ for a total of 3500 additional HHpoints. TPG values that as $2.10 but I place a higher overall value on them myself particularly if it tops up your balance towards a redemption it may be worth it.
-Using the Amex Platinum you get the base + 5000MR valued at ~$50 but worth far more if it would add to a balance or goal for a premium airline award ticket the value increases.
-Using the Amex Everyday you get the full base points plus your initial cost reduced by $50 as those Amex Offers tend to apply within the billing cycle. If your focus is minimizing spending it can be the better value.