Fitbit

I've had my Fitbit One for a few months now, and have found it a huge motivational tool to get me moving and out of my sedentary lifestyle. I just make sure it's in a pocket in my clothes (or clipped inside my bra - as per the instructions - if I'm not wearing anything with pockets in it) and it measures my steps, flights of stairs climbed, and calories burnt. I wear it in the supplied wristband when I go to bed to monitor my sleep, and only take it off to charge it or take a shower (it's sweatproof, but not waterproof).
If you do get one, go online to personalise it - you need to log your weight, your weight target (e.g. loss or maintenance) and tell it your average stride length. Without these bits of personalisation the calorie count and distances won't be correct.
I now us MFP to record all of my food intake, and the Fitbit software to record all my exercise, and have found them both to be very motivational.
I've lost about 15 kg (2 stones) in 4 months. I'm no runner, but the stair-counter and step counter are very accurate for me as most of my exercise is based in my own home. It's also pretty accurate when hillwalking, although you need to keep moving for the hill-climbing bit to be accurate — it doesn't count part flights of stairs, for example, so if I go upstairs at home it counts as "1", but if I go upstairs and rest half-way up before continuing, it doesn't count as anything. I didn't realise this when I first got it, and was proud of myself for climbing a really steep hill, and gutted to see it counted as only "1" as I'd kept stopping. Recently, I climbed the same hill without stopping at all, and it was recorded as "13", which is pretty much what I'd expect.
I've bought myself a rowing machine, and when I use it, I merely record the time, distance and calories burned from the rower onto the Fitbit webpage, and the calories burned are reflected in all the stats (and passed across to MFP to give me an "extra" food allowance if I've burnt enough of them!). As others have said, the Fitbit won't record such things accurately, but it doesn't claim to do so.
If I'm just pottering around the house, the steps recorded are pretty accurate, but the distance won't be as good as my stride is not consistent, but if I'm out and about for a proper walk, it is pretty accurate as it knows my walking stride length. (If I ran, I'd need to tell it my average running stride length, too).
I'm now "moderately active" as opposed to sedentary, and am motivated to become more so, thanks to my Fitbit One and MFP.
If you are motivated by numbers and graphs and trying to beat your own "best", then I definitely recommend it. Yes, it's "just" a fancy pedometer, but one that is accurate for what it purports to do, and doesn't need to be clipped to a waistband. It's neat and easy to wear in a pocket (although that also makes it easy to lose if it's not a secure/deep pocket!), and will even tell you the time and double as a silent alarm clock. I'd really miss mine if I had to be without it now . . . . .

I really like my fitbit flex but I personally don't think it was worth the $99 I spent on it. Since you wear it on your wrist the step count is always off. I can sit right here and just doing stuff basic it will claim Ive walked 40 steps. However I think its close enough to right. May be off by a few hundred steps a day. I also don't trust the calorie burned that it claims because sometimes it higher than I would think it would be for a simple walk. I don't eat the calories back that it claims unless I know I did a workout and know its pretty accurate. I do however think its great as motivation. If I see Im close to a certain number of steps I will make sure I do a little more to hit that goal. Especially if close to the 10k steps. Ill walk on the treadmill a little more if Im at 8k or something. For that reason its great. I think its a really expensive step counter and I think You could get away with buying a nice step counter and a heart rate monitor and get the same results you would just have to log your exercises itself. I link mine to myfitnesspal and I actually use it more through this site then the fitbit site. It shows your calories burned per day based on your TDEE and if you do more activity then it will add on top of that. You know your TDEE because of myfitness pal and you can add exercises based on a heartrate monitor and get more accurate calories burned logging yourself. If your a electronic nerd like myself fork out the extra money and buy it though. You will like it for what it is. The Sleep thing is way off.. If I set it sensitive it counts all the small jerks you do when going into REM sleep and if you set it to normal sensitivity it does seem to be sensitive enough because I know nights I struggled to sleep that it claimed I slept better than I did.

My husband got me one for Christmas as well and I must admit, at first I was a little disappointed. But, after a week, I am getting officially obsessed with it.

I find myself checking it throughout the day to see how I'm doing and if my steps or calories burned are low, I will adjust what I am doing to get extra steps in.

It definitely keeps you accountable and motivates you to keep moving throughout the day to reach your goals.

The wristband was very annoying at first to put on, but I read some tips on the Fitbit website to soak the band (just the ends of the band, and not the Force itself) in HOT tap water for like 2 minutes. I did this 2-3 times and now it goes on easy peasy.

I love it so far. We'll see if I stick with it!

I have the Force and love it. I definitely feel it's worth the $130. I have a friend at work who actively competes with me, it's a great motivator. The only thing I don't like is the fact that the distance measured doesn't seem to match up with my run tracker app or my treadmill. I don't know which one to believe! Overall, I recommend it, great little tool that really helps keep you on track!

I used to have the FitBit Ultra but it ran away from home. I immediately replaced it with the FitBit One. Amazing motivator but I would stay away from the wrist mounted ones since they tend to be less accurate with activities when your hand is stable, like cycling.

This I had a day I wore y fitbit one on my wrist all day and the calorie burn was higher even though I did the same thing as normal.. but I love mine and it's an eyeopener on how much you do or don't move