Unless the Cue Balls are made by Aramith they are junk. Only Aramith balls are made to exacting standards. Today there has been a large influx of balls from China and other Asian countries, these balls will ruin your cloth in a very short time.
Only Aramith balls have a exterior layer that reduces friction on your cloth from striking the Cue Ball. For instance have you ever seen a tables with little White spots allover newer cloth that will not brush out. These are friction marks, and they are actually burns in the cloths surface. When the Cue Ball is struck hard and especially during breaking a great deal of heat is generated at the cloths surface. This is why you will see the White lines running from the Kitchen to the rack area on both sides of the table.
In addition many cues balls have a different weight, in most cases this is only a gram or two. However, on a good table this will effect the length of the roll, and for people with a weaker stroke it can effect the action on the Cue Ball. This is why many people prefer the Tournament Red Circle Cue Ball. This ball is lighter than most others, and this is what lower level players like about it and why it is the preferred ball used in League play. The Measle Ball is heaver than most, and this in my opinion makes it a better practice ball than a light ball. This will help you to develop a good sound stroke, and it will give you the ability to see if you are putting spin on the ball when not trying to. However, the same effect can be achieved for a lot less money by using a Striped Ball as your Cue Ball.
To close, I would not use anything but Arimath Cue Balls like I said above. I also prefer the Brunswick Centennial Ball set and the Blue Circle Cue Ball that Aramith makes for Brunswick, in my opinion these are the best Balls on the Market for consistent play, for over all wear, and for consistent weight.
Have a good night!!!!!!!!!