I believe that this program is a great Photoshop alternative especially when used in conjunction with Apple Photos, Iridient Developer, Capture One Pro or the like. The price is great at $50 but it goes on sale pretty often for $40. Performance wise, I find that it runs slightly slower than Photoshop during processing time but it balances out when editing and being able to see the effects that processing choices will make before you select them. File support is good across the board and not having to convert items to smart objects is a nice move on part of Affinity developers. The different modules take a little while to get used to in knowing where certain functions lie but it gets easier over time with consistent use. Being able to choose to work within an entire colorspace workflow based on whatever the user prefers is a nifty feature whether you what to do RGB, CMYK, LAB, etc.
If you don't need some of the more Photoshop advanced features like working with 3D objects or integration into other Adobe programs then this software will work perfectly fine for the majority of users. Also it's great to have cross platform compatibility and not have to worry about subscriptions. I actually decided to cancel my Adobe Photography plan today (before renewal kicks in) and will stick with Capture One Pro 10, Affinity Photo, Iridient Developer, and DXO (when needed) for optimal lens correction/denoise functions.
*Pro-tip for those interested in cancelling the Adobe Photography plan. It often helps to contact Abobe customer service over the phone v. cancelling online. While online they attempted to charge me 50% the cost for the remaining time until another 1yr renewal (which would've been another 3.5 months of payment. They can override this extra payment over the phone. Be aware they will attempt to talk you into staying on or offering several months for "free." So that's what happens if you try to become subscription free.