Shoot strait, few have dents or are misformed, shoot efficiently and havn't chopped yet
none that I have seen
I used these one day while playing against guys with guns way better than mine, and they were more skilled. I know, I'm not saying that it was their guns that beat me, but if you can shoot twice as fast as I can with just as much accuracy, it helps. Anyways though, I shot almost a thousand of these bad boys, and I never chopped one. They shot straiter than I was used to, and I could actually shoot them kind of fast without chopping them. I used them all day, and they served me well. Now, I'm not saying that they are perfect. Some batches of balls are better than others, and sometimes the weather makes a huge performance effect on your balls, but I had good luck with them, and would recommend them to players who want nice balls for a mediocre price.
I would buy these balls again. I can definately tell the difference between these Formula 13's and the other balls I've been using. BUY SOME... you know you want to...