When buying a new bike should I really be concerned about  miles. I have been looking at a Ninja 250 one has 1116 miles but has scratches on it from where it had been dropped (not to bad though) The other has 6680 miles on they are both 2007's is there a reason I should pick one over the other??  

At such low mileage, on both bikes, the more important question is, "How diligently did the previous owner do the maintenance?"

One of the more obvious things to look at is the front tire. Any signs of cupping at all, indicates someone who didn't check the tire pressure often enough, if at all. If that wasn't done adequately, you can bet other things were also not done.

Another thing to check would be how smoothly the clutch lever works. They should both work smoothly and easily still. If there's any difference in the feel of the lever, take the bike that has the smoothest lever movement.

regards,
Joe  

You could always agree on a price on the one you prefer, contingent on it passing a full used bike inspection at your local Kawasaki dealership.  Agree to split the price on the checkup if possible.  If it passes, great.  If not, find out how much repairs will cost, and decide if that's worth negotiating the price down to compensate for the needed work or to just walk away.

With few exceptions, there is always another deal to be had.