I have both AquaClear 20 and the Supreme Aqua (200L/h). From experience the AquaClear has a superior design. The media basket is much larger than on the Supreme and also allows you to customise the media to whatever you like. I think i should add that the Supreme uses a really thin filtering pad, that doesnt last very long. I've stuffed filter wool in the filter basket so that there is more area for bacterial growth, otherwise i wouldnt trust it to filter very well. The AquaClear is also quieter and is of much higher quality compared to the Supreme.
My friend has the AquaOne 200 and he says its really loud compared to my AquaClear. He thinks my AquaClear is much better compared to his filter. His AquaOne also uses a thin filter cartridge, and isnt filter media isnt as good.