I am very happy, but ...

PDF Expert is an extremely good product and I use it on my MacPro , iPhone and iPad. I use it mainly for proof-reading, reviewing notes and filling in forms. Working across various devices is easy and comfortable. The only issue I have is that working through iCloud does not seem to work very well: for example, quite often documents are shown in my iCloud account on my iPad but not necessarily on my Mac. That problem is usually solved by restarting the Mac, but that cannot be a long-term solution. I am not sure this is a PDF Expert or an Apple issue, I could not find further information on the PDF Expert site.

SasBaldi about PDF Expert – Edit, Sign PDFs, v2.0.1