I think it's best to practice on grass! Though if there's strong sunshine, be careful not to keep your ball in one place too long, since it starts burning really quickly.
And the balls don't break break that easily.. first you get a crack in it, but if you drop it again and again after you get the crack, then it will get bigger until it can break apart. Or so I've heard anyway.. so I'm always extra careful with mine now since it's already cracked.

Practice balls are a lot lighter though.. I know that when I use my practice ball now (it is also a bit smaller than my acrylic one), I keep losing control of it because I'm used to a much heavier ball.