Ordered mine at 2pm on Saturday and received it yesterday. It's a little smaller than I thought but still a good size. I actually just ran into a girl at work in the elevator who got her 42mm SG yesterday. The 42 might be a little better fit for me but for now I'll hold on to this one.
Now, once I got it yesterday it had 65% battery so I charged up to 80% and went to the gym. I used the "other" workout for my weight training and then did the stair stepper workout for...the stair climber. My initial thoughts are that it's cool but I'm not sure how accurate it is. I was getting different readings on heart and calorie burn from the machines at the gym vs the watch. it's probably somewhere in the middle as far as accuracy.
I think it's a cool device so far. I'm still waiting on my 38mm SG BSB to show up though I may cancel. I'm thinking about the 42mm now that I've seen one in the wild. Time will tell...