Since calories with step-based devices is ultimately based on pace and weight, your distance must be accurate and match if comparing devices.

So first compare steps for your average daily walking speed (not exercise, not grocery store shuffle) - do they match?
Even manually count steps for so many and confirm device saw them.

Then you'll need to confirm it is getting the correct distance off those steps, since it adjusts from a base stat of stride length.
So walking a known distance while you started an Activity Record to confirm it saw it right.

Also - since you have no outside accurate comparison - perhaps the Fitbit is more correct and Jawbone has been more wrong.

Curious though - why wouldn't you except the devices estimate of daily burn to base your eating level on - compared to you guessing at an activity level and maybe or maybe not logging exercise calories separately?

Or you don't have an eating goal that is already at a device to what you burn - and your extra activity creates the deficit to lose weight?

I am an UP (the original first edition one) to a Blaze and I love the differences that I can see.

For me, the differences are to numerous to mention but the steps and accuracy is something that I can say is a HUGE difference. Perhaps because of the technology difference, how I am wearing this to that and such like that.