There are rules but little incentive to follow them, because ignoring the rules is seldom punished, especially on the AMEX, PHLX, and PSE. If you want pretty fair treatment, route your orders to the BOX, CBOE, or ISE.
just21, Well I traded both the OEX and ES options having about a $3.00 value today and you know I preffered the OEX. The OEX often had only a .10 spread between bid and ask while the ES usually had a spread of .30. Also the ES has higher comission rates but it seemed that you could change your prices and cancel with out any penalty and there were .05 increments for changing price where the OEX is .10 increments above $3.00. You know one thing that is sometimes a plus with the OEX is that the MM is wrong and you can hit his price but of course he can then dodge you and use the time lag on you and you find his price gone and you are entered but no fill.