I’ve had two Fitbit Ones (because I misplaced one in a move, thought it was lost, bought another, then found the first), and I like it well enough.
My daughter has a Nike Fuel, and one of the items is pretty inaccurate, but I don’t know which one.
My daughter went to England with a friend, and the friend had a Fitbit. They would walk around, her friend would sit, and my daughter would walk around, looking for interesting things. Once they walked from the train station to a stately home. Her friend stayed in the garden, but my daughter walked down to the house, walked around the house, walked in the back of the house to look at the lake, then back to the garden. That evening, their step count was about the same. I gave my daughter my Fitbit to wear while she wore her Nike band, just to see, and the Fitbit always had more steps. I don’t know if Fitbit over counts or Nike undercounts, but there was a big difference.
It seems to be accurate in comparison to itself, though, so if I walked 5000 steps yesterday and 6000 today, I am confident I walked about 20% more steps. Whether I really walked 5000 and 6000, I don’t know.
The floors climbed feature hasn’t been accurate on either of mine. A friend of mine and I laugh about it. I think the best example is the day I had more than 20 floors climbed and I hadn’t climbed one. Since I don’t care about floors climbed, I ignore it.