I used a bunch of different apps over the course of losing 75lbs. By the end I was using six different websites and a few devices. I found QS looking for something to manage all of my data. Nothing I have seen so far really did it for me, so I set about building one myself. I have an app that does the below stuff, and then some. What do you not see on the list that you have been looking for? What will it need to have for you to be interested? It works in all modern browsers, and is responsive(switches to mobile).
I hope to be in alpha by the end of the month. So far here are the things you can do with it.
Screen shots attached.
Track Stats(Any Stat)
Track Nutrition(10k Foods adding more soon)
Track Activities(Did you know dog sledding for one minute burns 5 calories?)
Graphs and Reports
Community with users and groups
Following, friending, and completely private accounts.
Social features - Walls, notes, etc.
Gaming aspect - Points awarded for logging events/meals etc.
Device Integration(Withings and BodyMedia right now)
SSL encryption + delete your data anytime(Export your data to csv)
 Picture Albums
 Device Integration (fitbit and others)