This was something I was wondering about and since I saw some others asking I thought I'd throw some initial results out there.
Push-ups: It did really well on these. Only had to adjust the reps on the first, of three, sets.
Sit-ups: Over-counted these by 5-8 on 20 rep sets.
Squats: Counted these as well as the push-ups.
Pullups: Really strange here as all three sets were over-counted by as much as double. All were dead-hang, no kipping. So somewhat disappointing.
Calf Raise: These were hit or miss. All sets needed to be adjusted, some upward some down.
Although this was just a short session overall it worked okay. What I wasn't expecting is that it does something similar to stroke recognition and the only execersizes it didn't do well with were the leg based ones. It picked up on the push-ups, sit-ups, and pull-ups perfectly. It saw one of the squat sets as sit-ups, one as squats, and didn't bother to guess on the other. The calf raises it had no idea.
Like with swimming you don't see the recognition until after you save the activity and you can go back in and adjust/correct each set.
The biggest glitch I had was when editing the reps of one set I accidentally hit the side swipe area when it was on the screen where you enter the weight and it jumped to 995lbs and I couldn't get it back to 0. It was either 999 or 1.
Heres as link to the activity on GC. https://connect.garmin.com/modern/activity/1985373116 (I hope the forum software doesn't butcher the link)
Looking forward to trying out the Yoga app after my run.