Yes it does differentiate between speed and also altitude (so it knows if you're walking up hill). I put my MFP at sedentary and then it logs my fitness activity from my Fitbit. I really like it and would recommend.
I got one a couple of weeks ago. Have enjoyed using it but I wish I had kept the box because I'm worried that in six months time ill be bored with it and want to sell it on eBay and I'm sure it will fetch a good price.
But it is making me move more and I like a good graph, I like targets and this fitness malarky can get a bit dull - nothing like getting an achievement badge for climbing 50 flights of stairs to make you feel like you are 8 years old again - I can't believe I am suckered in by the badges but I am. [shocked]
Pm me with your user id and we can be "friends" - oddly that really helps to keep you moving too - as it ranks your weekly steps amoung your friends.
I'm seriously considering getting a fitbit, but would like to know a little more about how it works?
I get an allowance of 1200 calories a day as I have a sedentary (desk based job). I walk to and from the bus stop, to the sandwich shop for lunch, and around the office but don't count this as exercise. If I wear a fitbit, would it give me extra calorie allowance for this? I am worried it may over calculate what I can eat? Conversely, would it deduct calories if I have a particuarly sedentary day?
My other question is whether or not it differentiates for walking speed - ie a stroll to the library with my toddler must burn less calories than a brisk walk when I'm on my own. Does fitbit take this in to account?
Any other important things I should know about a fitbit? I think I prefer this to the nike+ fuelband and other alternatives as it will sync to MFP and is also discreet to wear.