Usually calling a dish "cafeteria food" is a put-down. Well, this IS a cafeteria, so what did you expect?
You're not going to be blown away by any of the food here. It's decent though, and it's not very expensive either. The Swedish Meatballs are always a solid choice--not stellar, but pretty tasty. Anything else I've had here has really only been "meh" at best. Nothing bad, but nothing that made me want to return either. Although, again, this is a cafeteria; so, I wasn't let down because I wasn't expecting much.
I don't recall the service ever being friendly. Strange because it would seem that IKEA would be a pretty cool place to work...it would SEEM that way anyway.
Overall, if you find yourself hungry whilst shopping at this gargantuan mega-store, then you probably won't be let down by most of what you get at the cafeteria. Just keep your expectations low.