Quote from Zuizo:
Level II is practically useless for stocks trading over 3mil a day.
In my experience as a trader, when another trader who appears to be intelligent and more or less experienced states with complete confidence that one or another tool is "practically useless," and then some group of traders start competing with each other over how demonstratively they can chortle, there's a good chance that something very useful and practical - not to mention profitable - is there to be discovered and adopted.