Ideally, I'd just love a single app where I can sit down and monitor my progress across cardio, lift and diet.
Pick two. FitBit app sucks for tracking lifts. When you log it as an activity, lifts are all bunched under "Weight lifting (free weight, nautlius, or universal-type), power lifting or body building" with options for "light" or "vigorous" activity. You quantify by TIME. If you're only looking to show calories burned that's probably all you need, but it's no rep-logger. Speaking of, which app do you use for that?
Back to the device. I got a Force myself, but I'm not sold on the elevation tracking yet. I live and work in two-story buildings, yet over the course of a day I only racked up 5 floors yesterday. I'm sure it only counts elevation gained, but on the other hand it's fucking supernatural how forgetful I am, so I'm always up and down the steps. Will see if this improves.
A couple things if you get one... 1) Get the Force over the Flex. It's water-resistant, which you'd think would be Day-One shit for electronics that you strap to your sweaty, disgusting body, but the Flex is not. My coworker Eric water-damaged 3 Flexes before giving up on them all together. 2) Order now, or be ready to wait. Mine was ordered in late October, but couldn't be fulfilled until last week. Not sure if they're intentionally throttling supply, or if it will just be Christmas of the Fitbits.