I'm a IHG Platinum (and Royal Ambassador as well), and am pretty happy with the upgrades I've gotten when staying at non-IC properties.
Here are some of the upgrades/benefits I've gotten in the last few years:
USA:
HIX: Upgrade to larger room, and big bag of snacks/drinks.
Asia:
CP SIN: Upgrade to suite.
HI BKK: Upgrade to better room. Fruit/chocolates
HI BKK Silom: One level upgrade, so booked 1 level up, and got club floor/access.
CP CGK: Club floor room/access on award stay.
I know I've gotten more upgrades and such, but these are the ones off the top of my head.