I just did a quick SPG vs HH. I don't know if I am completely off here as I did it in a rush. But I think the grass is not greener at starwood.
HH:
80k points / nights
rate = $350
value 0.4 cents / point
This means 7 cents per dollar spent on hilton property as Gold (double dipping points and points, if not double dipping then 6 cents per dollar).
SPG:
25k points
rate = $350 dollars
value of 1.4 cents / point
4.2 cents per dollar spent on SPG property as Gold
I did not use property vs property comparison, I just took a hypothetical value of a higher end Hilton and SPG as $350 and used an almost top rate at hilton and second to highest at SPG.
Unfortunately the calculation above is highly flawed as there are very few properties that charge the high season cat. 6 rates with Starwood and if they did, the rate would likely be much higher. It is more likely that a $350 cash rate would be a weekday rate at a category 4 or 5 property which would be 10k or 12k. Also SPG gold members now get an additional 250 points as an amenity. Thus the rate with SPG is going to be much higher than the calculation above.