They are doing fine for the casual user and you can't beat the price.
However, as I started using it more professionally a few years ago, there are some real problems with long standing bugs in some areas.
My biggest complain at the moment is Art Boards. I use them for almost all my work. Allows me to work much faster when working on a suite of related projects.
However, they are the most broken of all features. Probably half of all the Affinity photo live effects are broken in art boards. Also, not sure which is worse, Affinity or the users. I've opened so many bugs on art boards, to have users push back and say it is not a bug and then Affinity ignores it. They say it is not a bug because most don't use art boards as they never grasp the use case.