I struggled with a small BGE - mine is one of those (not uncommon) which is temperature deprived. None of the other sizes suffer from this problem. An email to the mothership got the useless reply "Mine works". Replacing the fire grate did help and the BGE now will reach 500°, given an hour.
I solved the problem by buying a BSK. No problem reaching 700° (which the same size BGE will also do). one big advantage - the BSK exterior can be touched when cooking at 500°. the exterior of my egg is 375° when the cooking temperature reaches 500°.
I got the BSK on sale for $650.
Broil King Keg for grilling beef
Charbroil TBE for chicken
MAK One Star for for pork and MOINKS
Small Green Egg for decoration