I found the Fitbit to be the best activity tracker I have reviewed so far -- small, quiet, convenient, with a full-featured web site included at no extra charge. All Fitbits feed into the same personal profile web page and work with the Fitbit app, although you can only use one at a time to update your online account. Here are the various models:
Fitbit One: This model debuted in late 2012. It uses Bluetooth to upload to a cell phone or tablet app, and can also upload wirelessly to a USB dongle. Review: Fitbit One
Fitbit Flex: This model is encased in a flexible wristband, to be worn both day and night to track steps and sleep quality. It has no display other than five small lights, so you are dependent on accessing the data on an app via Bluetooth or through the wireless USB connection and viewing your dashboard online. Review: Fitbit FlexFitbit Zip: The Zip lacks tracking for stairs, sleep quality or stopwatch. But connects directly with smartphones via Bluetooth (in addition to the USB connection to computers). It has a long-lasting button battery so you don't need to recharge it. Review: Fitbit Zip
Fitbit Ultra: This model debuted in 2011. The display is brighter than the original Fitbit, which is a welcome improvement. It also tracks stair climbing and has a stopwatch function. It is rumored that the Fitbit Ultra will be retired in favor of the Fitbit One.
The pedometer has only one button and it automatically resets each day. To track sleep periods and sleep quality, you press the button for a couple of seconds to start and stop that function. But otherwise, this is foolproof.
Size: The Fitbit is smaller than most pedometers and very convenient to wear or carry in a pocket.
Noise: The Fitbit is silent.
Accuracy: The Fitbit appears very accurate and correlates well with other trusted pedometers. I experienced one case of reduced steps when it was clipped to my waistband at an extreme angle.
Display: The LED display on the original was too dim to read outdoors. They made it brighter on the Ultra so it can be read outdoors, although better in indirect light rather than bright sunshine.
Battery: The battery recharges via a USB base station plugged into a computer. A full charge should last about 10 days. The unit can save seven days' worth of data before needing to upload.
Accessories: It comes with a wristband to wear it while sleeping to track sleep quality, and an extra clip for thicker waistbands. It doesn't come with a security leash. I immediately added a leash from another pedometer when it popped off my waistband in the restroom the first day I wore it.
Getting a Fitbit and Getting Started
Costs: The price as of September, 2012 was $99 US. When you buy the Fitbit pedometer, it includes use of the web site for no additional subscription fee. There is an optional fee per year for a Premium membership which includes more in-depth reports and personalized training. However, the basic reports seemed more than adequate for me.
The Fitbit comes with a USB base unit which both uploads data wirelessly and recharges the Fitbit's internal battery. On first use, you install the Fitbit Service Manager software and register for the Fitbit web site, and set a few basic bits of information about yourself. Weight is needed to calculate your calories burned. The set-up was easy.
The data automatically uploads any time you are within about 15 feet of the base unit, you never have to remember to do it.
To upload away from home you will need to use a computer on which you can install the software and which has a USB port, and bring along your base unit.
The iPhone app and Android app let you add food and activity to your online log, but you can't upload the step data from the Fitbit itself with the original Fitbit Tracker or the Fitbit Ultra. Bluetooth has been added to the Fitbit Zip, Fitbit One and Fitbit Flex.
Recharging Trick: Sometimes the Fitbit Tracker and Fitbit Ultra don't seem to recharge when put in the base unit. We discovered that if you put a rubber band around it to hold it in better contact with the unit, you solve that problem. The Fitbit One and Flex have a different charging dongle that doesn't have this problem.
Your Fitbit Dashboard
Calories: Graph shows calories burned every five minutes, color coded for intensity. It also shows the calories you enter via the Food Log. You can review past days.
Activity: A pie chart and a graph of steps and activity every five minutes are displayed. It totals steps taken, distance, and an Active Score.
Sleep Efficiency: If you wear the unit to bed in its wristband or just clipped to your nightwear, and remember to start and stop it in sleep mode, it tracks your sleep pattern. This displays with a sleep efficiency score, when you went to bed, how long it took you to fall asleep, times awakened, how long you were in bed and actual sleep time.
Journal: You can track your mood each day, allergies and any custom log you want to keep (smoking, strength training, alcohol, stretching, anything). You can also journal information about the day.
My Stats: A weight tracking graph is shown. You can view 7-Day, 30-Day and All-Time Best for steps, calories burned, miles, active score, and very active minutes. You also see comparisons between you and all Fitbit users, updated weekly.
Friends: If you have friends who use a Fitbit, you can see how you compare with them for steps, distance, active points and very active time. You can also join groups and compare yourself to the group.
Food Log: The food log is easy to use as a food diary. Once you enter a food, it adds it to a quick pick list. It also allows you to create your own "food" if it isn't already on the list of 50,000 different foods, so you will have it available to choose from for future meals. You can create meals so you can easily add them to your daily log rather than adding one food at a time. While I found their list less comprehensive than I would like, users can always use our free Calorie Count site to get calories for a recipe and then use that in the Fitbit food log. You can use the iPhone app to add food and activities to your log throughout the day.
Activities: You can add other physical activities you did and you can edit your walking step record for those times you forgot to wear your Fitbit. You can save your favorite workouts to quickly add from a pick list.
Weight: You can track your weight in several ways. You can track pounds, body fat, and body measurements.
Heart Rate, Blood Pressure, Blood Glucose: Those who wish to track this data can easily enter it and view graphs.
Apps and Integration with Other Programs: The iPhone app and Android app lets you update the food and water you have throughout the day and activity, but it doesn't read the data from the Fitbit. You can see your Fitbit data that has been uploaded through your base unit. Fitbit can integrate data with Microsoft HealthVault, Endomondo, and Nike+ as well as several other tracking systems. Fitbit Apps
Update: Breakage and Improvements in the Fitbit Ultra
My original Fitbit Tracker succumbed to stress and simply fell apart after 15 months of wearing it most days of the week. The plastic elbow simply gave out. The warranty is only for 12 months. I could have avoided this breakage if I had used the provided belt clip holster rather using the Fitbit as its own clip. But I like wearing it flat as its own clip and will continue to do so with the replacement, even though I know it may break in a year.
The Fitbit Ultra replacement also includes stair climbing tracking and a stopwatch. These are nice improvements. They aren't enough for me to order one while my original was still working, but nice to have in the replacement. If you find an original Fitbit tracker on sale, go for the bargain unless you really want to have the stair climbing display. The Fitbit One won't have the same breakage problem as it is a one-piece unit that slips inside a neoprene clip case that can be replaced. However, some people have had trouble with it popping out of the case and getting lost.