Hmmmm never heard of these! I have a Big Green egg, Weber gas, and 2 Weber charcoal. Now I have to convince the wife to spend $500 on an outdoor griddle!
22 and 36 have teh most flame per square inch, thus the only 2 to consider. The 28 has 2 knobs for control and the flame is spread out over a larger surface area. The 36 has 4 knobs and the flame covers the griddle completely.
22″ is great for travel and for my needs but no way I would buy a 28 or 17.