I picked up Affinity Photo for Windows in the recent sale (the whole suite, actually) as companions to the iPad apps, and have found them to be very slow to open on my PC.
I'm running Windows 10 (1909) and the specs are:
Ryzen 1700X
32GB RAM
1TB Samsung 960 Evo NVMe SSD
I have asked for feedback about this elsewhere, and people are telling me that it's unusual, with Photo launching in "about 12 seconds" from a SATA SSD or "about the same amount of time as Photoshop CC". Well, I don't have CC to compare against—I've been stuck on CS5.1 since I don't want to pay a recurring subscription for software.
But the Affinity apps take so long to open that I'm finding them very inconvenient to use, and have stuck to Photoshop to get work done rather than learning/experimenting with Photo.