Well as far as being versitle you just can't beat it. The only time I have had focusing problems was in pretty din lighting (indoors in the evening with one lamp on). I find I generally have to use a flash with this lens when shooting indoors. However the zoom ability has allowed me to capture great shots both indoor and outdoors.
I usually leave the 18-200 on the D3000 which I drag around with me most everywhere I go just for versitility while the D300S I take more time to consider the lens, lighting etc...
Quite a few of my shots with the D3000/18-200 are see something, grab camera, zoom and click. The shots would be missed or have to be severely cropped with most other lenses. So I do really like the lens for this reason.
Lastly I will mention I have had a few focusing issues between 190-200 at times for no apparant reason, but not too hard to overcome by going to 180mm or manual focus.