List of all workouts and challenges with best scores

Don't think there is. All other progress (completed challenges, FP added to your monthly total, best score for the workout) is usually saved, but in my experience if the game dashboards before awarding the stamps those are gone. Thankfully doesn't happen
all that often for me.

same here, seems to be related to challenges mid workout.

the first 15-20 mins I get no issues, 5 stars/green bars, then get a challenge come up and it continues to play the video feed at normal rate but the tracking colour bars, score and timer all lag.

really hope this gets sorted asap

I seem to have the same issue. I didn't use Xbox Fitness for a while, but when I finally did a few workouts again, a few days ago, I noticed there were much less scores from friends in the messages than there used to be. I also didn't get any friend challenges
while doing two of the Yo:30 workouts.

I didn't pay that much attention to it. Of course it could just be my friends started to workout less. But I have a lot of Xbox Fitness users added to my friends list (literally hundreds). It seems unlikely that many of them stopped playing.

You didn't list Living Dead. ^_^ Of the ones you listed Firefight. Specifically Arcade. Unless I'm doing challenges. Then it's Score Attack.

I am in the same boat as the op, just got mover II (lame name from Mover I) ...

I got the intro movie and it asked for my stats all over again, I didn't think much of it. Did a workout and got a couple of stamps and saw I was on stamp card 1 ... wtf???

All the challenges and my previous month stats are all there just no stamp cards.

I will agree with the more rigorous exercise the kinect decides to disappear for 2-5 seconds dropping your score way down as it thinks you left... sometimes have to redo it to get the 5 star challenges.