How is czusa customer service

I've had good luck/experience with them. I haven't had to send a firearm back for work. I've needed parts on several occasions... Dropped a pistol slide off the cleaning bench and bent the front night sight blade. Then another time I misplaced a set of scope rings for a 452 22 rifle. Both times they sent the parts to me under warranty at no cost to me including shipping even though they were both clearly my fault. I wouldn't have any reservations about dealing with them.