You’re totally right, the resolution of those PDFs and PNGs is not as high as we would like, and I’m sorry about that. It has to do with the framework that Mockups 3 for Desktop was built on top of, and not something we could fix without re-writing everything.
So we are re-writing everything.
Our newest web apps already have the new exporter, so if you need a high-resolution export, email me the project and I’d be happy to do it for you. Otherwise, the new exporter will be shipping with our new desktop apps later this year.
I’m sorry if this is a pain for you, Somers, but it won’t be for much longer. If there is anything we can do to help in the interim, let me know!