This is just what HP say in their marketing: a BREAKTHROUGH.
I've had HP bubblejets and laser-printers and recently a Samsung colour laser (the last one being a disappointment in everything other than the price). This HP is brilliant. It prints at incredible speed and with perfect colour rendition. It just spits out the pages like a photocopier.
As far as I can judge from the ink consumption, it's going to be months and months before the cartridges need replacing. It's a 'proper' printer at a decent price - nice one!