I think they'd be great. If I could afford them for over 200 total trees of all sorts, about half fruit trees, I'd buy them. But at about $15 a crack, not in my budget. Ironic that something made from garbage costs so much.

I have a couple around very small trees. It's useful to lay down a little landscape felt before the ring goes in to help discourage grass, which will eventually work through the mesh and become entangled otherwise. As denninmi says, at $15 each you wouldn't want to buy too many. Plus side is they are a tidy interface with the lawn and last for years.

Yes, they are a bit more pricey than I'd like, but I wonder if they'd be worth it.

I might try a couple out just to see how it goes. That is good to know about laying down some fabric beneath them.

My concern with them is that mice or other rodents/pests might make their homes beneath them. Also, I don't know how large of one I'd need to be worth it.

What other types of mulches and/or weed barriers are good for fruit trees? I really want to control weeds and conserve some moisture in our hot, sandy soil.

Thanks for the responses! I do appreciate the input!