As a Diamond Amb for the last two years, IHG works for me and it is my primary. Won't repeat what was posted above as I agree with most points: Marriott hotels and loyalty program are meh, Hilton one secondary with an ok program, the breakfast T&C are like a space shuttle operations manual, Accor has nice hotels horrible program (I started out in this game years ago with Fairmont Plat which spoiled me) and Hyatt never has any hotels where I want to go.
I have to say I find your lounge listing (separate thread and this post) a strange hill to die on, if you stay at IHG 100 nights plus, you will quickly figure out which brands have lounges and a quick look at the hotel page will fill you in. I don't get it. I have to say the lounges at ICs I have stayed at are much better than most Marriot and Hilton lounges, some by far. Keep the credit card status warriors out of there IHG thanks!