Print output quality is all you would expect from a modern, fast, business laser. Text is sharp, with no spatter, and even at small sizes shows no signs of stepping or jagged edges. It's at almost offset-print quality.
Greyscales for fills and graphics are also well reproduced, though surprisingly the dot pattern is coarse enough to notice. This 1,200dpi printer appears to default to 600dpi for most tasks, unless deliberately set to fine print.
And that's not too easy to do; it doesn't appear to be possible to set the resolution explicitly anywhere within the driver, even for photo prints. The best you can do is set the driver to Photo and, in Advanced Settings, select maximum print quality and sharp halftoning. It's not exactly obvious and the print, while showing plenty of detail and good fill patterns, shows some banding down its length. You get the feeling Epson would rather you didn't print in this mode.
Epson claims a noise level of 56dBA when running, but we measured peaks of 65dBA at half a metre, the kind of distance you would stand from the machine, when waiting for a print job to finish. The Aculaser M4000N is not particularly unusual in this, but its high print speed means the sound level is fairly continuous when printing.
The imaging cartridge, which comprises drum and toner, and the fuser maintenance kit are the only consumables on this machine. Although they are £150 and £200, respectively, the page yields keep the page cost down to just 1.64p. While this is low, it's not the best we've seen from a mono laser. The Lexmark T642 produces page costs of 1.47p, for example.
While this is a robust business laser printer, it's hard to see how it can justify such a high asking price. Other printers we've tested with very similar specifications come in up to £150 cheaper and you can get a more than passable colour laser for £700. Features like walk-up printing are missing here and unless you're aiming for a very high duty cycle, you're paying a lot for the high speed.