Meg -
I really don't know how to be any clearer than I've been - there really are ZERO hardware problems with my Watch. None.
There are some rather interesting design choices, and the software seems to use models which have issues with uniformity of data reporting -- choosing an active calories model based on heart rate, lean body mass and time, rather than one based on weight, time and distance, for example -- but there are exactly 0.0000 hardware bugs in my Watch.
The reason I mentioned you and Winston is because your answers aren't the canned "Calibrate your watch" (very well calibrated, as proven on a treadmill) and "Go to the Genius Bar" (though you seem to keep fixating on that as well) responses I get from Jonathan.
Anyway, the horse it has been beaten enough. Other than waiting (forever ...) for Apple to decide to provide the ability to do a direct comparison between every other fitness app and tool I've got and itself, I've got all the info I need. I never have trouble getting my "Stand" time these days - I make sure not to carry things around in my "Watch" hand. I don't have to swing my arm or anything, I just drop it by my side and I get "You did it!" in short order. If it takes more than a minute I give my arm a wiggle and then I get "You did it!" When I'm doing working out, I wait until I'm finished cooling-down and a big chunk of calories I didn't get while warming up all show up -- that's because the active calorie model is based on heart rate, so I get "credit" for the calories not recorded warming up while cooling down. No needed for repeated calibrations and resets - I just get the "cool down" calories I missed during "warm up", which is correct for a heart rate based model. I keep my body fat percentage updated every so often (1% lost since starting to use the Watch, yeah, me!) and that helps with the accuracy as well.