So I've started using the Hotels.com program instead of Hilton recently, mostly because I calculated that I'll be earning free nights faster this way.

One issue I have with Hotels.com is that they charge my credit card as soon as I make the reservation, compared to when I book hotels directly and they charge me upon checkout.

I have 2 issues with this:

1) If I book my hotels when I book my air tickets (often in advance) I am out that money until I complete my stay and am able to expense it. I also don't get receipts from the hotel so I have to remember to keep my email confirmations and print those out.

2) If you change your hotel reservations a lot, which I do, you end up with a laundry list on your credit card bill of charges and credits from hotels.com and (at least on my card) there is no indication of the date of the stay or location of the stay. It took me forever to verify the charges and make sure I wasn't being double billed.

Just thought I'd throw that out there for anyone reading this thread.