My Dad hasn't been to Ikea from what I can gather. I like it for the same reason as meglorien, and that for the money its goods are of a better quality than other popular brands that look similar. Our shelves & desks have done excellent service, and before that a cot (lasted 2 kids and would have lasted more had someone else's water tank not burst all over it).

Obviously, just like anywhere else that is popular (e.g. shops in general?!) going there at a weekend or bank holiday is a bad idea. Tuesdays, or after dinner time, or 23/24 December have all worked for me - virtually empty. I hate crowds.