I just thought I'd come back and post something about this. I got the fitbit flex, and love it!
Its so nice being able to track your steps, and not needing to remember to put something in your pocket every time you go out. I've already been hitting my 10k steps a day... and even hit 29k on one day... damn my legs hurt the next day!
Anywho, if anyone is considering getting it - I'd highly recommend it. I've lost 5lbs in just over 2 weeks, simply by hitting my 10k target, and doing a few lengths every now and then