Hey! Your absolutely right, Apple has got down an awesome native PDF editor & annotator and that Windows do not have their act together for native apps.

The direction Good Annotations is taking however is to be able to do all of that collaboratively with other users. The stuff you see today is hopefully the first step.

Device compatability is obviously a tough one because there are so many different devices out there creating alot of edge cases. At the moment we're following the data to get things off the ground. Chrome & Desktop. We will be looking at touch support in the near future