Worked perfectly!

Used it last week during the labor of my daughter. Was way easier than writing down with pen and paper. My husband just pressed the button and then could get back to concentrating on me. The times I needed to record it, it didnt take too much brain power. Was helpful to be able to edit for times we messed something up. I even emailed my early contraction record to my husband at work to tell it was time for him to come home. App helped up decide when to leave for hospital, which was 45 mins away.
All in all, Im not sure of differences in paid vs free, but download paid version and support the developer! Believe me, this app will be invaluable when you are ready to use it!!

aemo45 about Labor and Contraction Timer, v1.4.3.1