I picked up some new contact juggling balls a bit ago. I found them mentioned on the Ministry of Manipulation.
They are much heavier and harder than a standard stage ball (to me, it seems like someone just made a stage ball with walls an inch thick).
I like them a lot, they have much more mass, and are easier to roll than the lighter stage balls. In terms of danger to nearby objects, they are somewhere between a stage ball (which will hardly break anything) and an acrylic, which will break most anything you bounce it off of. I wouldn’t want to drop the new one on a bare foot, but it’s much easier on things it bounces off of than an acrylic. But I also don’t wince if I drop it on concrete, unlike my acrylic. 
Definitely a sticky surface, only for one ball contact.
I got mine from firetoys.co.uk, expensive to get shipped to the US, but quick.
Recommended.
