I've used this tool on two motorcycles so far and what a time saver! Total time to seat the upper and lower races was approximately 4 minutes. It seats the bearing races perfectly without any problems. Another plus is that you are able to do a number of different make bikes with the various sized seating attachments that come with the tool.
I have the Tusk kit, and can't speak to the Park Tool kit; in the picture the park tool kit shows less of the disks for pressing, but in the tusk kit it's two of each size - the park kit might be more different sizes, since there's five. I also don't see the manual driver handle in the park tool kit. In the tusk kit, the handle in the case next to the long rod is designed to fit in to the press rings and be driven with a mallet, which I found quite useful for final seating on my project.