For a start, it's fast; very fast. That's for a good reason, says Serif's managing director Ashley Hewson. "Photoshop is an amazing piece of software," he says. "But the problem is, it's built on 25-year-old architecture. When that architecture was being created, Adobe couldn't have anticipated the incredible developments we've seen in computers since. Which means that they're now struggling to adapt Photoshop to take advantage of modern computing power."
In contrast, Serif has built Affinity Photo, like Affinity Designer, on an entirely new codebase, which allows the software to take advantage of the latest hardware; and the speed boost is palable. It means, most notably, that all the edits you make happen in real-time, with no lag or scrolling wheels of death.

Also striking is the way the software remembers every single change you make, and lets you retrace your steps if necessary. So you'll never get prompted 'Are you sure you want to make this edit?' because you can always undo it.
Unlike other Photoshop rivals, it includes end-to-end CMYK, 16-bits per channel editing, LAB colour, RAW processing, ICC colour management, and Photoshop PSD and 64-bit plug-in compatibility.
Compatible with OS X Lion 10.7.5 and newer on Intel 64 Macs, it's available in English, German, Spanish and French. And users of Affinity Designer will be pleased to know that moving assets between the two tools is smooth and intuitive.

Affinity Photo is available to download now in free beta from: https://affinity.serif.com/photo.
Once the full version launches,  it will be available exclusively through the Mac App Store for just £39.99/ €49.99/$49.99 (subject to App Store matrix adjustments) with no ongoing subscription charges and all updates free for the next two years.
If you don't use a Mac, though, you'll have to wait a while to try Affinity Photo. While the development team do want to build a Windows version, there's no firm date for that, and it will probably be a long time coming.
That's because Serif is currently focusing on building a third tool, an InDesign alternative called Affinity Publisher, to be released later this year. Following that, their next priority will be building iOS versions of all three Affinity tools. And to complicate matters, Serif is continuing to produce its older budget tools for the PC market, aimed at the non-professional consumer market.