I completely agree - the IKEA dill mustard is quite delicious: the flavour is remarkably well balanced, and the mustard itself is creamy but still has a bit of bite to it.
My overall favourite mustard is Löwensenf extra sharf (extra hot) mustard. It's the one in the red bottle, and it's a good hot mustard - I find it's really hard to get a good hot mustard in North America, so that's my go to.