Opinions: Fitbit?

So I'm thinking about getting a pair of fitbits for me and my husband with our tax refund this year instead of buying a years membership at a gym. I need the constant reminder to get up and move and going to the gym would eventually become a hassle because I would need to pack up all the kids into the car (I have 4 under 8 so be understanding) and pay for the on-site childcare at our Kroc center which is the only one I'll go to.

The fitbit would track everything and give me challenges, hubby and I could challenge each other without him turning into a drill sergeant (his step dad sent him to boot camp twice, he's not military) since we are already mildly competitive on our mobile games. It would also track our summer hikes at the local hiking trail.

Do you ladies have something similar or have a fitbit? Do you do this with friends or family? How well does it work? What do you like most? Least?

I want to get close to my prekids weight (100 pounds needs to go) while hubby wants to shed 50 pounds and gain muscle.