Jawbone has a competing product, and even Samsung Galaxy S4's latest phone includes some of the functionality (ie: a pedometer) people look to Fitbit for.
My anecdotal experiences with GS4 vs my Fitbit One shows the Fitbit One to be superior, but I'm more likely to forget my Fitbit than I am to forget my phone.
iPhone has an app called Moves which is remarkably accurate (http://www.moves-app.com/). I'm getting fairly similar results from my jawbone. I believe the discrepancy is due to the fact that I don't have the phone on me when I'm at home.
My anecdotal experiences with GS4 vs my Fitbit One shows the Fitbit One to be superior, but I'm more likely to forget my Fitbit than I am to forget my phone.