Something I've ranted about often. The cross platform support for Serif's own products is near non-existant.

Pageplus doesn't support/can't import native drawplus files.

Compare this to adobe where you can import an .ai file into ps. and it keeps all your layers intact. I think that PS was originally meant to be used purely as a photo editing tool until artists discovered it and then it took off as an image creation too and adobe started to support that side of the product too.