The team my 9-year-old boy is on uses these in practice and will even take some swings on them during the games. His coach also uses them with his 13 year olds team. Not saying the zip and hit is the reason why, but my boy's team has only lost 1 game in over 3 years of baseball, including fall ball. So it's not a bad team, and they use it quite extensively.
At home we have the Hit-Away baseball mounted to a pole and it works great. But, I can't really take it with us. So, we picked up the zip and hit. Now, when the wife goes in the grocery store, we park far enough out for me and the boy to attach it to the back of the vehicle and take some swings in the parking lot. When we go to a Red's game or a Florence Freedom game, it's a big hit in the parking lot there as well. I coach 3 soccer teams year round and the boy and me can squeeze some hitting in between games.
So just for the portability alone, this thing gets 5 stars in my book.
Also, about the review stating his kid now swings over the ball because it doesn't drop like real pitches would. You can make it drop using several different techniques that are described in the directions that come with it. After you get his confidence back up, you might be able to give it another try.