The Surface Pro's digitizer pen works great out of the box with Windows 8-style apps, but in desktop mode, you'll probably find that it misses the mark when you're trying to hit tiny menu options.
Fortunately, this brilliant Reddit contributor, Alxqs, posted a simple hack that converts the Surface Pro's standard 16 pt. calibration to 100 pt.
We've tried it ourselves and it works like a charm. Photoshop's dense menus and tiny icons are no longer a problem.