I'm a little disappointed in the ability to draw on a PDF in Skitch. I review a lot of papers and in all of the other tools I've used, one of the best way to make notes is to "draw" on the PDF (essentially just handwriting). However, in Skitch, this isn't really possible because when you zoom in to do the writing, picking up your pen at all ends the annotation you're currently working on. This means if you want to write a letter like a 'T' or 'H', it's pretty much impossible. As soon as you pick up the stylus, the previous line gets locked and now instead of drawing the crossbar, you're selecting the previous line again. I realize that one of the major design decisions for the Skitch editing style is to allow all of the annotations to be selectable, but not being able to write on the PDF is a big pain. I know that there is also a text box option, but this option doesn't seem to work well across devices. If I set the text to flow a certain way by resizing the box on my iPad, when I open up the PDF on my Mac, the text box doesn't reflow and flows all the way out of the page which makes it unreadable. I also can't make the text small enough to fit in many of the margins for the kinds of papers that I'm reviewing.