I'm in Shanghai every few weeks, and have never noticed the Ikea (for the UK element on here, I know where the B&Q is!).

I've eaten in Ikea in Warrington & Wednesbury UK, Heerlen Holland and Logan Aus.
Food is pretty much the same in all of those - cheaply priced, good "stick to your ribs" kind of food, from a 1Euro breakfast to a Au$3 meatball and potato portion.
Don't go expecting gourmet food and you won't be disappointed