My first claim was two weeks ago. I called IHG, received a confirmation email ("we validated your claim and have contacted the hotel...") after two hours and received final confirmation ("Per our Best Price Guarantee, your first night has been changed to a free night") after 20 hours.
I loved the hotel and had a wonderful weekend. I was even given a room with a great view.

Currently I have two more claims pending. I filed one of them three days ago and the other one 4 days ago. I received confirmation on the phone for one of them and confirmation via email for the other one. The email says "We have contacted the hotel and requested a verification of the lower rate you found", though. Well, I still think that both will be ok.

I really love this guarentee. It seems to be sometimes inconsistently applied but I am not mad at them. For me its fun to search for lower rates and I feel very thrilled once I found one. Additionally it gives me the chance to stay at incredible hotels for a low price/for free.

Good luck to all of you!