Check out the reviews on Amazon. I have found the negative reviews often provide the best information. Here is a link:
http://www.amazon.com/Singer-9960-Qu...owViewpoints=1
I personally would not buy a Singer because its reputation for current machines is pretty bad. Also, in just skimming the top negative review of this particular machine, the fact that it struggles with layers of denim indicates to me the motor is not strong. Also, I would never in a million years use 600 stitches! For me, reliability and stamina would be worth 400 stitches or so.
From what I have read, Sears Kenmore machines (which are made by Janome) deliver the greatest bang for the buck. Janome has a good reputation too.