I would lump (if you can excuse the pun) the BGE, KJ and Primo in the same category, the others in a level lower. I am a KJ owner for the last four years and could not be happier with mine. That being said, the top three are all going to cook the same, it's a matter of personal preference and a few minor physical differences. I really like the finished hardwood quality of my KJ and the durability of the gasket. I have cooked on mine at home and in competition, as well as hauled it out camping, it holds up, no issues whatsoever. Price point being key, you save a couple hundred bucks versus comparably equipped BGE or Primo. Ceramics of the top three are something I feel everyone should own just for the fun factor. I can't bash any of them, they are all outstanding cookers. Just speaking from personal experience I would never get rid of mine.
PNWBA - Hayden, Idaho http://www.facebook.com/BC2BBQ