I have the IKEA high chair too. Doesn't have a 5 point harness, but haven't found this to be a problem. DS can't climb out of it. I am always with him while he's in it anyway. Soooo easy to clean and only $35 for the chair and tray. You can also get an inflatable cushion ($5) to put around behind them which stops them wriggling lots but I found I don't really use it.