Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: there are better alternatives

I compared Nikon 18-200mm, Sigma 18-200mm and Nikon 18-70mm/Nikon 70-300 mm side by side. At the same focal lengths, Nikon 18-70mm/Nikon 70-300 was better than the Sigma 18-200mm and the Sigma was better than the Nikon 18-200mm in terms of image quality (sharpness and color saturation). If you like the convenience and want to have a wide range zoom lens for your DSLR. The Sigma is better. Alternatively, an advanced all-in-one camera like the Sony H9 or Sony H50 will give you as good or even better picture quality as well as other important features (e.g. wide zoom range, high shutter speed, high ISO, etc).