I am one of the many users that faced erratic mail rules behavior after upgrading to Lion. It works sparingly as it like, not like how you wanted it to behave!!
I found the following in the default mail rules that came with it, even from the old days of Leopard and Snow Leopard. (See attachment below, mark in red box)
The Apple Mail rules contain a line to "Stop Evaluating Rules".
I don't know if this is the culprit and had removed this line.
So far, after removing it for 4 hours, Mail seems to be faster in running Rules and nothing had gone wild with rules.
Thought of sharing this to those who are still pulling hair with Mail Rules. No harm trying this simple one.
I found the following in the default mail rules that came with it, even from the old days of Leopard and Snow Leopard. (See attachment below, mark in red box)
The Apple Mail rules contain a line to "Stop Evaluating Rules".
I don't know if this is the culprit and had removed this line.
So far, after removing it for 4 hours, Mail seems to be faster in running Rules and nothing had gone wild with rules.
Thought of sharing this to those who are still pulling hair with Mail Rules. No harm trying this simple one.