I use the fitbit and you are correct it is not automatically any good for cycling.
My key reason for buying one is the fact that it tracks sleep. I have been experiencing a lot of problems where I wake in the morning still feeling exhausted. I had suspected the reasons for this, but using the fitbit gave me all the information I needed.
So here is a typical bad nights sleep:
The key problem is the average person needs about 90 - 120 minutes to hit REM sleep. It is only required for a matter of seconds to be of use. If you don't get to REM sleep your body has got to catch up or it will suffer. I had indeed been suffering for a long time!
Here is last nights sleep:
As you can see a good solid sleep until I woke about 03:30. But that one REM sleep has done me a lot of good.
Oh and the key to why I keep waking? You won't be surprised to know that the main reason is alcohol! It doesn't need to be much, but the wrong alcohol. So I know to be careful of some of my favourite whiskies if I want have a good sleep!
I also find it useful for tracking my daily walking exercise and when I review it, I can make sure I reach the various targets I set myself.
Since biking I add in the distance and time it takes which also calculates a rough calorie burn.
All in all I think this is a really great product and recommend it to anyone who wants to track what they do or as in my case if they are worried about their sleep patterns.
Best regards
Chris
