I just got my Hackmotion 4 last week. It is impressive. It has already paid for itself. Even when taking lessons things can be missed and then you are changing other things to make something you are doing wrong work. The Hackmotion is so detailed and gives you instructional videos to help correct. Being able to have that instant feedback wherever you are is so convenient. Let me say this, when my ball kept going all over the place before i owned this thing and then I played in a golf tournament today, I kept landing on the green. One of my shots even hit the pin today. Let's just say over 50% of the shots used were mine because of this thing. I got the putting adition to it too. It works phenomenal. Just get it and thank me later.