Fitbit one -- More info please

WarmDontBurn

So I am considering purchasing the fitbit one and have read a bit about them but wonder how it integrates with MFP.
If it calculates your daily burn does it adjust your goals here?

I am very much a numbers girl on MFP so my goal and my net must be pretty close.

I have a HRM as well and eat back my exercise calories -- just wondering where the fitbit numbers come in to play and what I can expect should I purchase it.

Thanks in advance for any and all help!