My use case for PDF is not only viewing but also editing content, from files sent by another entity. I use for that Acrobat Pro which is somehow expensive for what it does and has evolved into a terrible user interface over the years. I recently tried another PDF solution on AppSumo at a similar price point, PDF Reader Pro. Although it does the job, the UX is far from great.
So I tried UPFD. From the Mac App Store's version history I see that in 5 months it has made significant progress in terms of features. In terms of use, I was able to edit very quickly and exactly as needed a rather complex tax form. Clean UX, multi-platform support, good progress. Despite the current limitations expressed in the Questions tabs, this piece of software does what I need and seems headed in the right direction. Refunded the other one and finally cancelling my Adobe subscription.