my fitbit is tiny and clips to my bra. The one measures steps, stairs, calories burned for the day, has a timer on it that you can use for an intensive workout or sleep patterns. I also like that it encourages me to add petals to my flower. Love getting my 10 petals. It also links up to the computer and SP.
The Fitbit One is about $99. Fitbits customer service is great and there is a large following on FB. There are some really good motivational people. I like the charts on the fitbit site and you can find friends who use it as well and challenge each other.
The flex is water resistant but it is more of a bracelet and it doesn't do stairs.
It will be a personal choice if you want to change. I have tried a variety of pedometers and have found nothing motivates me more than my little buddy.
| current weight: 250.0