I have been demoing it for the past week. It is an interesting app that has potential. Some things still need work and developing and even documentation, since I can't figure out some features and some of the pictures are in Chinese (I think that is the language?).
For simple motions, it seems to count really well. So deadlifts and rows for example, in which the travel of the bar is a really smooth simple motion. These are default built in gym exercises so that may help. Other motions I have tried, like a clean and jerk with a kettlebell, are all over the place. it counts one rep as about four, but to be fair to the app, there are 3-4 different motions to that compound exercise (I squat slightly as part of the press, and it counts that squat as a rep as an example).
As a feature request, I find the 3 sec startup counter to be way too short. So I would have the be user configurable, or set it to longer, 5 secs or even 10 secs. The app starts counting immediately. I take time before starting a lift and so would prefer to start the watch and the count down, and then get ready to lift. So when deadlifting, I might take 10-20 secs getting ready with my hands on the bar, before starting (and the app may count adjusting your hands or shifting your body weight as reps during that time).
I haven't done that many variations of exercises, but the 3 sec timer also contributes to another issue: counting the first rep properly. When bench pressing, the first action is to lift the bar off the rack. No one that I know would count that as a rep. So you don't start counting reps until you bring the bar down. This app counts that initial lift of the bar as a rep.
For kettlebell swings, it seems to count fairly reliably; except, it seems to add 1 rep, which may be as I put the kettlebell down (I haven't managed to read the watch yet during a swing but I think this issue is with the last rep and not with the first, assuming I start the motion before the 3 sec countdown finishes). So I have done 20 reps of swings on multiple occasions and ended up with a count displayed as 21. The few times I didn't have 21 I think were my error, not the app. so that is pretty good overall. The other app I used in the past, Fitcounter, wasn't this consistent and does not seem to work anymore for me at all now.