There are definitely many styles of longbows, all the way from very long string follow straight bows, to very curved short bows with recurve type risers. All that makes them long bows is if the string doesn't touch the limbs when strung. Tournaments may have other qualifications, but the point is that there are many different styles. Therefore, the very best way to pick a longbow is to get where you can shoot and try out a bunch. A good traditional tournament will have several makers as vendors who will let you take a bow to the targets and try it out. There will also be several vendors selling used bows you can try and just about everyone will let you shoot their bow at the warmup targets.
Personally, I always wanted to love Howard Hill style bows, but I never met one that was pleasant to use. I prefer highly R/D longbows with more substantial risers.
