Right, we also purchased Sketch licences for $99/year, which is still the cheapest. Then comes Figma professional for $144/year (has a free plan as well) and the most expensive Adobe XD (start from $696/year).
Of course if you work with images and require Photoshop or Illustrator, it will make sense to go toward Adobe ecosystem.
If it is a smaller company and needs only UI design tool, might worth look into Figma or Sketch.
Most of my freelancer friends all use Figma. It has a free plan which is more than enough for a solo designer, who is on budget.
Would be interesting to know where Affinity Designer would position itself on this market 
Worth also considering where these tools are going in the future. Design systems and real time collaboration is still something what they work on.
Big corporates need other tools as well, like virtual white boarding. This is where FigJam (Figma’s virtual white board) is coming to the picture. Invision, the prototyping app provides a really good competitor (freehand) compatible with Sketch. Adobe is behind a bit with this topic.