Had a bad experience as well with Hyatt BRG. Wasn't really looking to do this, but happened to notice the rate on AAVaations.com was $10 lower than my already-booked Hyatt rate; plus with the 20% discount on the lower rate, I figured it was worth a quick call. This was booking only hotel, not a package. AAVacations site said they absolutely guaranteed the room & price once I put in my cc. Called Hyatt and ended up spending 50 minutes on the phone, which was insane but it become the principal of the thing for me.
When I first called, CSR told me AAVacations is one of their "300" web sites listed as not qualifying for BRG. Agent spent 20 minutes trying to recreate what I found on AAVacations' web site, put me on hold to speak with supervisor, then they called AAVacations. Final determination was AAVacations issues a "voucher" and that their price and room confirmation is not guaranteed when I book; therefore not eligible. He said as a good-will gesture Hyatt would give me the room at the $10 lower price (no mention of the 20%). I asked if that rate would be an eligible rate and he said no; I said forget it. A few minutes later my phone rang, it was the CSR saying they didn't realize I was a Diamond so another goodwill gesture--they would insure that $10 lower rate would be an eligible rate. I'm thinking I must need my head examined to spend so much time on this, but thanked him.
Today I decide to call AAVacations and they tell me emphatically that when I book with them, the room and rate are absolutely guaranteed. Yes, they send me a voucher which I take to the hotel as proof that I've paid.
Anyway just wanted to agree that this Hyatt experience smacks of the Hilton BRG experience, which surprised me. Even worse, I spent nearly an hour on the phone--at least the other brands do it via a quick form & e-mail.