TPG's valuations are generally based on premium cabin (business/1st) award bookings with transferred miles. When you transfer to airline partners, there's essentially a 25% bonus when you transfer in blocks of 20,000 points. For example, 100k Starpoints would become 125k SkyMiles, more than enough for a pair of most US-to-Europe Main Cabin roundtrip flights (generally around $1,000 each) but that's not really a good example of redemption value.
The reason a group of us are in what may appear as the SPG Cult, however, is that since SPG and Marriott are not fully combined yet, Starpoints transfer to Marriott at a 3:1 ratio, meaning you get 3 Marriott points for every Starpoint! Marriott has some very lucrative award options. One is 5th night free when booking with points - and important to note that you also avoid hefty hotel taxes and fees when booking with points. Another is the vacation packages where you get X number of nights in a Marriott hotel + airline miles on the airline of your choice.
Marriott awards are also based on a 9-tier category system and are not revenue based (like Southwest RapidRewards which will change depending on the actual cash price of the flight). A category 9 hotel room will always be 45,000 points per night whether the cash price is $200/night or $1500/night. Because I can only take vacations during absolute peak seasons (school-age children) and I usually stay in Category 8 or 9 Marriott hotels, I get ridiculous value on Starpoints doing things like April in Paris on the Champs-Élysées or Times Square on New Years Eve.
The other interesting side-effect of the 3:1 ratio is that a combination of the Amex SPG and Platinum cards completely blows away the earning of the Marriott cards or the Ritz-Carlton card for any possible type of spend, including at Marriott. Also, even at just the 2.7 cpp that TPG values it at, this is 15,000 Starpoints in addition to the 20,000 Starpoints you would have earned anyway for a total of 35,000 which would be $945 by TPG valuation, or 4.725% back in travel rewards on that $20k spend. Again, I've been consistently getting 7+ cpp on Starpoints, although I know my usage isn't exactly normal.
@K-in-Boston wrote:Just logged in to my Amex account and saw this under my SPG card:
That'll probably be an easy extra 15,000 Starpoints for me! 20 grand in 3 months? Challenge accepted, Amex! Check your accounts*; signing up was a breeze:
* Edit: @simplynoir posted a link to the DoC article on this below and here is a direct link to the 15k offer. There are also lower offers available per the DoC article.
Just a quick follow-up here and a question... I surpassed the $20k in spend on my Starwood card in the 9 weeks after posting this (and boy does my current reporting utilization and exceeding my credit line mid-statement before a payment posted show it - ouch!). Normally, Amex spend bonuses (including my original 35k SUB on the SPG) post right away for me, often mid-statement. I only got the 13k or so Starpoints for regular spend credited to my account with the statement that just closed, and didn't receive any bonus on the previous statement after I had surpassed $10k.
Has anyone else received their bonus(es) yet for this promotion? Or does anyone have any data points from previous targeted spend bonuses on the SPG card? Not nervous yet, but I've got my eye on either a very high end Nights & Flights package or possibly 2 lower-end Nights & Flights packages (1 now, and if I can get some additional points in August for the upgrade or new app for SPG Luxury card, I was thinking maybe a week at the Sheraton Tiranë in Albania and the Courtyard Belgrade in Serbia with 240k Air France miles in exchange for 540,000 Marriott points) so I want to make sure I can make this happen fairly soon.
Just looked at the original email. Guess that answers my question. 
Heh. Yeah, that's the thing. I'm on the fence between a "wow!" redemption using my tried and true redemption strategy for Cat9 hotels before the change along with the Air France reward chart before their changes vs. just waiting until after August and going with either redemptions on what would currently be Cat 4/5 hotels in cheaper countries (see above post) or going big with a post-August 1st "Standard Category 7" redemption for what would currently be a top tier Starwood or Ritz-Carlton redemption (but becomes off-peak/peak Category 8 next year). If there's availability, some of those Cat7 bookings from August 1st to December 31st are going to have killer value since Cat8 pricing doesn't get introduced until next year.