I LOVE my FitBit One! I'm getting the Aria scale soon too.
I sync it with LoseIt and just love that combo. LOL I did laps around my bedroom last night because I only needed a few hundred steps to hit 10,000. It definitely motivates me to move and not sit on the couch during my 2 year old's nap time. I get really annoyed with myself if I'm not close to 5000 steps my midday and I find myself thinking up activities to do with my son that will get more steps in. Totally worth the money!
FYI - If you are a government employee (includes military) and get the gov't discount through Verizon Wireless, you'll get a discount if you order the FitBit through them. I think that's the cheapest way to buy one.