I've got a Charge, and it is really accurate. I like it.
However, if you mow the lawn with a push mower, or use a belt sander, or something that vibrates the Fitbit it will give phantom steps. But if you understand that it's great.
I really like how the charge counts how many floors you go up. It has a barometer and can tell when you go up.
I wish a regular watch with Fitbit technology was available. I'd buy it.