I have the best results with the Associated ball cups. They can be snapped on with a pinch from a marshal or on looker. I have seen countless times when people give up trying to pop on a ball cup and then give up and hand the car to the driver. I have even tried and said many times. How the hell did something so hard to snap back on pop off in the first place. Losi ball cups mainly.

They will all end up bending breaking or popping off. The inner mouth wears down and pops off. But the outer never wears and so popping back on is difficult.
AE's are designed to pop on easier, they have a wider mouth on the outside. But the inner is precise till it wears.

Same as all the other brands.
Never had any worse results than any other basher type that seem to be to tight and not fit freely. If I have one that starts pooping off frequently I just put on a new one. I would rather a ball cup pop off than snap a ball stud or steering knuckle. I have seen this time and time again.

I would stick with the AE set up. Good luck none the less. There all about the same in 1/10 scale but to me AE are the best over all design and performance ball cups IMO.