HRM or fitness tracker??

I have a polar T4 and until recently used the fitbit flex. I am not a fitbit lover. I am generally very active and it way over estimated my calories burned and the number of steps I took. So I broke up with fitbit. But that being said, I know many many people who absolutely love it so I guess it's different for each person. I know many people who use both.
I love being as accurate as I can with calories in vs calories out. It makes things so simple. That's why I'm just sticking with my HRM. I recommend the polar. So my vote is for HRM. It really depends on how you are going to use it. Do you want something motivating to keep you/get you moving? Then the fitbit would be good. If you want something to motivate you to burn more calories and increase your heartrate during workouts? Then HRM. Depends on how you will use it. That's my experience on it.

Do you have a smartphone? I have an app called 'Sleep Time' that tracks my sleep and I have a friend that uses the app 'Sleep as Android'. It works well for me. Then I have a Garmin 305 with a heart rate monitor that I wear when I exercise. (I don't think it would work wearing it over an entire day but Garmin may have another product that would).

Funny timing for this to pop up. I have a Fitbit Flex (Activity Tracker) and a Polar FT7 (Heart Rate Monitor).

I bought the FT7 about 2 years ago when I was doing Insanity to keep track of calories burned/heart rate/etc. I continued to use it at the gym during cardio days. I stopped using it for awhile, but for reasons mentioned below, I started using it again. I have to say for cardio based activities it's very nice to see what your heart rate is and how many calories you actually burned.

About a year ago I decided to buy a Fitbit Flex since I was walking a lot and wasn't using my HRM to track walks/jogs/etc. I was curious how many steps I did in a day, like you I was thinking the sleep activity tracker would be awesome since every article about getting in shape states you need proper rest. I can honestly say the sleep tracker, for me, is useless on the Flex. You turn it on manually and then it monitors how active you are. But if you can't sleep and you are reading/watching tv/etc and aren't moving around it counts that as sleep. For me at least I have problems going to sleep some days and it can be hours of inactivity physically that isn't actual sleep (aka just laying there trying to sleep). I do love the Flex though, on days where I haven't been active when I check my dots and only see the initial one it does motivate me to get out and do something. To me at least that's worth the $99.

Two additional things to note about the Flex that I have found in my time using it. First would be the band only lasted about 6 months. I bought 3 more bands for $30 at Best Buy so that should last me for 2 years or so which I would assume is about what the lifespan of the Flex would be, but who knows. Electronic gadgets tend to have 2 year lifespans so I'm just assuming. I would plan on buying some bands, or at least knowing you'll likely need more, upfront. The second thing is I've recently started cycling and find my Flex absolutely worthless when cycling. The constant vibrations turn on/off the sleep tracker constantly and drain the battery. So I've recently started using my HRM again for cycling. There are workaround people find like putting the flex in your shoe laces and things but I'd rather just take it off and use the HRM since the Flex won't accurately track cycling anyway.

I haven't looked at the newer products that have come out recently, but I'd say get the Flex if you need motivation to get moving. Get a HRM if you just want more accurate calories burned and the ability to track your heart rate. If you want both and can afford it buying both would be beneficial.

If you're mostly walking as your activity, Fitbit might work well for you, though I have heard many reports of it overestimating calories burned. Although my walking varies each day, I don't walk purposely for fitness - I'd rather run or lift or do something of a higher intensity. I have both a Fitbit (for about 3 months now) and a Polar FT4 (for about 3yrs now). I prefer the HRM because it more accurately tracks intensity. I prefer to estimate my normal calorie burn to set my daily goal and then use the HRM to add in calories when I do something over and above (running, lifting, etc). I personally wouldn't have bought the Fitbit but work gave it out as part of a wellness program.