1. Focal lengths.
2. The quality of the image is at its best when compared with ultrasonics from competitors (sigma, tamron). Unless Nikon 18-200 can lose a little. As for the optical resolution, for an 18 megapixel matrix it is quite enough, in my opinion. Of course, not 15-85 and not 17-55, but still ...
3. Price for used - took for 13,000. Shot around the world, a small back focus on 18 mm, the rest was on target.
4. Stabilizer. Not the strongest, weaker than the same Canon EF 70-300, but not so voracious either. 2-3 steps gives. On imported resources, they write about him that he seems to be intellectual: i. E. unlike the mentioned 70-300, where it is 2-mode (1 - normal, 2 - for shooting in wiring), at 18-200 the stabilizer itself determines when to work in which mode.
5. Good design.
6. Fast autofocus.
7. There are few deviations in the quality of specimens, in contrast to the same sigmas, which must be chosen very carefully.
For the cropped Canon, at the moment, it's probably the best choice if you need ultrazoom.
By the way, maybe it’s important to someone))) The lens is quite large, larger than the Nikon 18-200, and it looks very solid on the carcass))) With such a weight, you can only hold the lens, you will get tired quickly by the carcass.