These roll-on bottles are excellent and they are durable. I dropped one on the floor and it did not break or crack. And they don't leak.
My favourite feature is the writeable label--I would recommend using a fine point sharpie to write with, as pen ink does not work as well.
The product flows out through the roll-on ball just fine.
I rate this 4/5 and will definitely buy these again. My only issue is the price point, which is a little high. Other than that, they are great.