iPhone and Workout Apps: which one?

ForeverIrish

I just upgraded to the iPhone 4S. So far, I really like it, especially the MFP app.

I'd like an app that I can use to keep track of my workouts or recommend excercises. What are you using, why are you using it, and is it user friendly?

Please forgive me if this question has been asked to death.

runnercheryl

I use Endomondo for walking and running, if either of those are your thing.