Of all of the devices that I’ve looked at, the only ones that I had any hands on experience with was pedometers. I knew how they worked, and I’ve always liked that they are simple but effective. They’re also not obtrusive, so I don’t have to worry about wearing it to work.
What’s kind of neat is that you can find pedometers integrated into fitness bands, so you don’t really have to choose. It’s more a matter of if you only want the step counting functionality or if you want all of it.
Here are the pedometers I found that are flexible and usable in a lot of different situations.