I don't think I have shot a Horne (don't remember it if I have). I have heard good reviews though.
Roy Hall of Navajo Trad. Archery has the same deal on his Navajo and Navajo II--same riser will accept either limb--the Navajo is the longbow, the Navajo II is the recurve (great bow and Roy is a great guy, btw). In my experience (I have owned a Navajo, and friend owns a Navajo II), there isn't much difference--speed is pretty much the same, they feel the same,.....the longbow was a bit quieter, but not much. The big riser on a 3-piece td really takes away from the longbow feel to me. Many of the larger tournaments have a separate class ("modern longbow"

for this type bow, if it is even allowed in the longbow class at all. If the Horne is anything like the Navajo, I wouldn't suggest getting both sets of limbs, unless you just wanted different weights because, with the Navajo at least, you still have basically the same bow with just a little different shape. As with any bow, try to shoot a few before you take the plunge.
Chad
Long Bows Rule!