The prints we produced with the Stylus DX8400 were good, but not marvellous. Black text still showed some bleed of ink into the paper, though pigment - with its greater particle size - should have stopped that.
There were improvements in the text and graphics prints though, particularly when printing text over coloured backgrounds. Here there was less feathering, so the text looked crisper than from a dye-based printer, such as Canon's PIXMA iP4500. A single page copy of the text and graphics page was better than many we've seen, with only a slight lightening of colours, but a generally good representation of the original.
Photo prints were smooth in tone, a function of the high 5,760 x 1,440 resolution, but a little too rich in colour. Over-saturation in darker areas of our test images tended to black-out detail that was in the original image. This can be compensated for through the driver, but the default settings should have done better by default.
Epson doesn't quote noise levels for its printers and one reason is likely to be the high levels it generates when feeding paper. We measured peaks of 67dBA, which is around the same level as a vacuum cleaner - you wouldn't want it printing by you while you were on the phone.
It's quite awkward to work out running costs for the Stylus DX8400, as there are several ways of buying ink. Each of the four cartridges is available separately, but you can also buy a four-ink multipack. Black ink is also available in a higher-capacity cartridge, though strangely these are only available in twin packs.
We used the twin-pack price for working out the black page costs and the multipack price for colour pages, as these are the cheapest ways to buy consumables. The black page cost, at 2.72p per page, is a little higher than average for a machine at this price, while the cost of a colour page, 6.61p, sits in the middle of the field.
The technologies involved in a modern all-in-one printer are now very mature and there are few advances to report in print quality, speed or page costs. The Stylus DX8400 does all the things you'd expect of a general-purpose, home or home-office machine, in a predictable and robust manner. It's noisier than its main competitors when feeding paper, but in other ways is a good choice.