Review (5/5): Great combs, great value!
Update: One year later: Most of my combs have cracked after daily use. However, I'm going to reorder. This is still the most sustainably-sourced material I can think of for a comb. This time, I'm going to oil them more frequently. I wasn't bothered by water spots, so I hadn't been doing it, but I think it will keep them from becoming brittle and may make them last longer.
The positive reviews left by others are all accurate. As for the comments about water spots, simply rub the comb down with any edible oil periodically, and you won't have any water spots -- I even use my combs in the shower. This will have the added benefit of distributing a small amount of oil on your hair.