The Fuel Band is a different device from most of the other fitness gadgets out there. It is more of a motivational device than anything else. The tracking on the that thing is questionable and the lack of being able to track individual activities is really disappointing.
To track runs or exercise proper a different piece of tech would be useful. I use the Nike+ Sportwatch for that.
With that said, I've been wearing a Fuel Band for the past 4 months now and while it isn't a great measurement of any one particular activity, it has been a great tool to keep me moving. I'm generally pretty active but there are days when I am just tired to due to work and life. The Fuel Band on multiple occassions has pushed me to get going especially on the crappier, rainier days. Times when I have been too tired to hit the gym, checking the fuel meter and seeing I'm only 200 away gave me the motiviation to get up and hit the goal either by a quick field trip to the gym, or a quick run around the block.
To be honest, the Fuel Band really shouldn't be measured against a true workout tracker as that isn't its intention despite the marketing campaign.