I train with these balls on most occasions and can safely say they are some of the better balls out there! I've found they are durable, which is a big positive with these plastic balls, when training and are decent for multi-ball!
I currently use the Donic Coach 40+ plastic balls in my coaching sessions. I am very happy with these balls. They are round and very consistent. The price is not to bad either, the plastic balls are definitely getting better.