I have not used the fitbit (I believe I ordered one, but never received it)
I have over the years purchased many HR monitors, pedometers, and the like. Keep in mind some of the following…
None of them actually do a PERFECT job calculating calories burned. You will see this in every forum that talks about this in detail - someone complaining that gadget x sucks cause of XYZ.
Accelerator only based pedometers use an equation to predict calories burned - this will come out the same whether you are walking/jogging uphill vs downhill - when obviously the calories are different.
Is an excellent pedometer. I have tested it walking - and it is dead on accurate. I have probably bought about 10 of these (some as gifts - some for myself - some for others)
The reason I mention some for myself is that I kept losing them. The only solution that worked was to TIE the PEDOMETER (not the holder it comes in) to my belt loop. Battery life was pretty good - and it is dirt cheap - has a great USB connector for tracking data and holds( I think - over 40 days of data). I have more gadgets than 99.9% of the population - and this is one of the best deals for the money of any gadget I have ever used.
HEART RATE MONITORS:
I don’t know if I have acid in my skin or what, but I literally have bought a dozen or more of these over the years (both polar and suunto). I like the data I can get off them, but:
I need to use EKG gel to get a good connection - no amount of water works for me - sure - I might get 10 minutes of perfect data, but it will be followed by gaps of several minutes (assuming my heart didn’t stop for minutes at a time).
Even though I carefully wipe them down after each use - they break on me. I am careful with the seals and batteries (on non sealed units) and something always happens.
I have been using this for over a year now and is my current method for monitoring daily activity. It is pretty good. I wear it all the time - except for when I am in water - or conducting - um social experiments with the opposite sex (and yes - in the interest of science - I have worn it then too).
The data it gives you is pretty good - and it tracks your temperature and sweat too (you don’t see that directly) - and calculates - calories burned, time laying down, time asleep, steps taken, and so on…
Not cheap (I think it is around $150, but a monthly fee of $8 or $12 (cant remember) a month.
I have NEVER lost it - I have broken the strap it came with a couple times - it is glued, so I just snap the fabric part under the plastic part (have to see it to understand, but is simple) - and that works great.
I would recommend this highly if you like data at all - as you will get lots of it. It uses more than just motion to track calories burned. It is not perfect - if you wave your arms around a bunch it will tend to overestimate calories burned, while if you do one of those perfect irish jigs - it will underestimate it. It does everything a pedometer does and more.
You can go about two weeks between uploading data - or recharging - and gives you a visual/audible beep when you need to.
Downside is no instant feedback like a HRM or Pedometer - I haven’t found that top be as important as I thought (I still do get and use a HRM during aerobic activity in addition to this). You can get a display for it, but it isn’t worth it.
I believe this is solely accelerometer based - but it does give you some cool data - including sleep patterns (which believe it or not - is possible to do fairly well using movement data). I just don’t see myself being able to use it regularly - I would have to tie it to my clothing all the time to keep from losing it.
They say 5-7 days usually between recharging (minimum of 3). I know I would forget and lose data, based on prior experience. If you aren’t concerned about losing it - or the battery life - seems interesting (and I probably will still get one).