Thanks for posting about these deals. The Affinity suite of tools looks like very nice software. I wouldn't blame anyone for being tempted to buy.My tl;dr warning is: Definitely make use of the 90-day trial before you buy, as you may be unhappy with the results.
I bought Affinity Designer in 2018 because, while I'm not an artist, I do occasionally need to make or manipulate an image here and there, and it seemed like really capable software and it was on sale.
So I bought it and played around with it for a bit, noticed some bugs and issues, including a serious performance issue. Then I posted on their forums to report the bugs or otherwise get support, and. . . nothing. No response to my post about terrible performance. But I was busy in my life with other things and wasn't ready to dive into seriously using Affinity Designer yet, so I kind of forgot about it. Then, about a year later, during another one of their sales, I bought the Affinity Designer Workbook. When it arrived, I opened it up and started reading through it so I could learn how to use the software. A within the first ~15 pages or so, still within the introductory chapter which explains the UI and basic tools, I noticed a few discrepancies between what the book showed me and what the software showed me. There was one button/tool I couldn't even find. But otherwise, as it explained each tool, I spent a couple minutes playing with it in the software to get a feel for how it worked and what it was for.
And that's when I ran into the big issue
. One of the tools, the Vector Brush Tool, slowed my computer down to a near standstill when I used it. I actually recorded a video of it where I spent ~10 seconds drawing a single curve and it took ~4 minutes for it to actually render what I drew.
Now, to be fair, this video recording shows it as being worse than it actually was. Because Affinity Designer used up all my CPU, my video recording software ran even slower, so it actually looked smoother on my machine than it looks in the video. But the important part is that it still took the same amount of time even when I wasn't recording.
One of their big and prominent claims is how butter smooth the software is and how it is always so responsive. So once again I went to their forums to try to get some support because either they were lying about how responsive their software is, or there was something wrong on my end that needed troubleshooting. And once again, there was no response to my post. Finally I complained loudly on Twitter and that got their attention. I got a response on a Friday and I was busy that weekend so I didn't get back to them until Monday. They asked for more information from me and had a couple suggestions I could try. We sent a couple messages back and forth over a couple of days and then they went back to radio silence.
After about another two weeks I complained loudly on Twitter again which prompted them to respond to the thread once more, but with a very unhelpful "there's nothing we can do." A little bit later, a different person from Serif asked me to try it out on another machine and see if anything changed, and asked for a video if I could record one. So I obliged and recorded my testing on another machine and posted the results to the forum thread. Can you guess what happened next? If you guessed "nothing" or "radio silence" you are correct!
So the software may or may not work well for you, depending on who-knows-what. The Workbook was outdated and/or incorrect the moment it arrived, and had printing blemishes (ink smudges or whatever) in it as well. And it's nearly impossible to get anyone from the company to respond to you when you try to get support.