I have a pair of semi-complete ten pi folded horns. They are nice speakers, but they are very large and not easy to build. If you don't have a large listening room, they take up a ton of space.
Also, prepare to have plenty of cash on hand. My Ten pi's will have cost me over two grand (canadian) by the time I am finished, because there are a lot of little intricate things you need for them.
Cool to have, though! :)
Adam