I had never used a foot pedal until I got my Hegner scroll saw, which came with one. The pedal was small and thin, and very easy to use. The only drawback was remembering to push it under the saw so that I didn't step on it unintentionally.
When I tried using the pedal that came with the Jet scroll saw, it felt like my foot was suspended in mid-air. I know that this is a standard design, but for my size 7 foot, it was just too large and high. It was easy enough to replace with the smaller one, since both types have provision for connecting a tool to the pedal.
Here's a picture that shows the size comparison for the two different types. If you're in the market for a foot pedal, it would be a good idea to try out both types to see which is most comfortable for you to use.