If you're looking to buy a stock, which one would you prefer to buy based on level 2?
Stock ABC .10/.12 8x2 (8mm's on bid and 2 on the ask)
or
Stock CBA .10/.12 2x8 (2mm's on bid and 8 on the ask)
Based soley on the above info, you would want stock ABC because there are fewer mm's on the ask which indicates that it will more easily rise with any buying pressure. In addition, there is a large number of mm's on the bid which tells you that it will most likely hold up under some selling pressure.