I'm a graphic designer / web developper. I use Affinity Designer as my 50% software for design, the other 50% is photoshop.
There is one reason that affinity is not my 95% and it is the guides management. As a web designer, all my design must follow some kind of grid, in which I move elements. Once my grid is built I dont have to move around guides, i just have to move elements. As much as I love affinity, the fact that when I take a border too close to a guide move the guide (an therefore destroy my grid) is pretty annoying.
Another feature that would need to be improved is that when you put an element inside another (the only way I found to make somekind of clipping mask) If I strech the parent objects every child element is streched which is not what I want. I understand the logic but having somekind of clipping mask would be useful).
Last thing, and I'm not fan of it but a friend of mine pointed it out, is the lack of some form of isolation mode. Isolation mode in illustrator could be defined as: "lock every element but this one and lock child items in sub group so they act as single items." He said its the feature that failed him (as for myself is the thing I hate in illustrator so take it with a grain of salt)