I have been doing my screen shots with snapzpro & am still struggling a little to make it feel like a natural habit.
I wanted to speak, however, to the advantages of capturing screens as pdf vs. the traditional (old school?) jpg or tiff. Many of the programs re-written for OsX now allow for not only exporting, or printing as, pdf, but also allow for importing and placing pdf. OmniGraffle, InDesign and Keynote come to mind. pdf provides a much better and more scalable image in these apps & is a pleasure to use.
pdf also allows for a one step, easy to open and look at, file for windows users, particularly those in an office environment with limited breadth of skill and software at their disposal. I have emailed jpgs in the past & had to explain that these could open in explorer, powerpoint, word or even excel. pdf (after what seemed like years of unfamiliarity in the windows world) is now pervasive. This allows for easy viewing with a double click in their email and, sometimes more importantly, simplified printing.
As usual - what works for you will depend on your needs and the needs of those that you are working with.
cheers,
Ian