I gave it a 10 because of price-to-performance ratio. Obviously this isn't in the same league as an L lens. But for a consumer-level lens it produces great shots.
I did a comparison between this lens and the absolutely fantastic 50mm f/1.8 -- same shot, both at 50mm, same aperture and shutter speed. At enough zoom to read the tiny letters below my TV's volume buttons, this zoom lens gave the prime lens a real run for its money in terms of sharpness. The 2 images are virtually identical.
It's slightly softer wide open at 28mm, but still very usable. Leagues above the 18-55mm kit lens, to say the least. This is now my primary walk-around lens and I don't think that will change until I get some L-series glass.