I LOVE my fitbit. It is always on my wrist - no fumbling for a phone - and it doubles as a watch. I love seeing my number of steps - I can challenge myself gradually to increase. I have the Charge HR which includes heart rate so I can monitor when I'm doing higher intensity exercise, but if you go down to just the Charge it's cheaper. I don't think I'd get the Flex since I believe it doesn't display all the information (i think you need to see more of it on your phone). Mine shows me time, steps, stairs, distance, heart rate. And when I sync it to my phone it lets me see how well I'm sleeping, as well.