The sponge tennis balls look great until you put them side by side with the real thing. Also, I assumed that they were "super soft" which they are not.

Excellent prop. I have the perfect bill to egg routine for this prop. You can show it and then conceal it easily in your hand. Well made and made to last. I will say that it does not squish down as small as most sponge balls. You can squish it down to about half it's size. That is enough to conceal a ball in your hand, but you would need to have pretty big hands to conceal more than two. You could hold make it appear you have a couple balls and produce four, but you probably couldn't conceal all four.
All in all, top notch and definitively will be of use.