This is getting silly. Put a number in front of a load of webnerds and they go nuts. It's a guideline - nothing more. The important figures are your click through rate, and even more important - your return on investment. A 10/10 keyword that doesn't make you money is pointless. Does your 7/10 get results? Y/OK N/Not So OK
Bingo Magda! Everyone wet their pants when adwords starting ranking out of 10 instead of "poor, ok, good, great" or whatever the hell they used to use. The truth is no change was made to their system except changing from a word system to a number system. (I'm sure they screwed with their algo too to try to crank more profit out). QS does matter, but if you're profitable at 2/10 then 2/10 is good in your case.