All excellent reading. Since it would take me forever to quote each individual section, I'll just respond with my thoughts here.
(1) Availability of awards. Forgive me for being relatively new to SPG here, but I'm not totally convinced about this No Capacity Controls thing. I've just tried to search for awards on two weekends - this past weekend in STL and four weeks from now in CVG. In both cases, all SPG awards were/are sold out at all levels of hotel from Four Points to Westin. I could book rooms in those exact hotels everywhere on the Internet - Expedia.com, Travelocity.com, etc. - but not at SPG.com. They had effectively manufactured a "sellout" situation by shifting their availability to the third-party agents. As folks on the SPG board have pointed out, I might have had luck invoking the Best Rate Guarantee to get a points-earning rate at the hotel instead of booking the Expedia Special Rate. But...I wanted a FREE room. No dice.
Marriott.com and beta.hilton.com had plenty of availability for award rooms.
Also, in the past, I've used two ALONs and two weeklong Marriott awards - a total of 4 weeks in Hawaii on all 4 of the main islands. I got those awards without any trouble, and I've never been top-tier. In addition to the Cincy stay, I have a weekend Marriott award stay coming up. I have never had an availability problem with either program.
My point is: if SPG plays games with their availability on my cheap Ohio weekend at Four Points, what do they do with their premium properties? Will I EVER be able to use my SPG points at a top-shelf hotel? I'm start to wonder, even as I am now starting to earn boatloads of Starpoints from the SPG Amex.
(2) The affinity cards: you have to take them into account if you are seriously considering the hoarding of hotel points. Their impact is MASSIVE - it can dwarf the impact of the hotel stays themselves, in some cases. But even if you do enough volume that it doesn't, why would you ever check into a Hilton on a points-earning rate with the (no annual fee) HH Amex?
(3) Others are bringing up Priceline again. Hey, you're singin' to the choir.
I wish I could use Priceline more and points-earning rates less. But I do have some business stays, and I do have some leisure stays where I am willing to pay more for the Homewood Suites/Residence Inn-type hotel, so I set up my calculations to help me determine where I should do those stays. I expressed my rewards in terms of # of Free Nights my personal favorite rewards: the Cat 2 weekends and the Cat 5/6 weeklong stay. I took dollar value out of it because I tried not to get hung up on whether I was really going to do that Cat 6 week in a good Priceline zone or not. I just don't know...
(4) Booking bonuses. Oddly enough, I generally don't get them that much. Then again, I usually pick a property that I like and then book it, so I'm not going out of my way looking for which of the three big chains happens to have a booking bonus at the time. I can tell there are a couple of serious mileage runners here who have hit home runs with bonuses upon bonuses with the programs. I haven't gone out on a purposeful hotel run since my pursuit of ALONs via cheap Hampton nights in 2002... My figures assume normal hotel stays. No "crazy" bonuses. Although an extra 500 or 1000 here or there would be nice.
(5) At the end of this all, I've decided to obsess far less about a hotel chain than I used to. Since I've made SPG Amex my primary card, I will always and forever be awash in Starpoints. Since I don't do heavy business travel anymore, I will never reach a top-tier. And since I usually like TownePlace Suites and Residence Inns, I'll probably sort of stick with Marriott for paid stays - but with an eye out for a good Hilton here or there, at least as long as they keep mailing me or my family free Gold cards.
That way, when I want a free room, I'll have a couple of programs to pick from.