Originally Posted by 3544quebec

$50 per 4 nights is $12.50 value per night and that $12.50 when spent will earn you another 25-50 SPG points (so 75c - $1.50 if you value your points at 3c each) That means you are getting a value of $13-$14/night for up to 12 nights at any SPG hotel
500pts/night is worth $15/night but only earned with Sheraton brand stays.

I don't see much difference between the value of any of the options myself except that I don't want to buy a Westin bathrobe.

Other than if you are spending over $8000 in 15 nights or more where the triple points seem the best option all the other options give a return of around 10% if staying at properties around the $150/night mark and your choice should depend on how many nights you are staying and the restrictions on number of awards within each option.
The free W/E night option could give a higher return eg if you pay for 10 X $150 nights and redeem for 1x $300/night property then your return will be 20% on your outlay. With similar figures and a 16000 point/night redemption choosing the 25% off award would get you a return of 800pts per paid night or around 16% assuming $150/night paid stays and value of 3c/point