Thinking a versatile walk around
Little slow and wide range so can’t be as sharp as some
Any input pro. Con
There are probably two questions that you need to ask yourself.
1. What are my expectations?
2. How often do I expect to use the extreme focal lengths?
I've considered this lens also, for the same reasons that you list. But in the end, it is a serviceable but mediocre consumer grade lens that isn't really optimally compatible with my modern full frame cameras. On the other hand, it's been around for almost 10 years, so it's not likely complete junk. If I am doing casual photography or taking snapshots, I use a DX camera for that. And I have an 18-200 DX Nikkor that I can use for that, if called for. It is also a serviceable but mediocre consumer grade lens, so it doesn't get used very often.
Please don't get me wrong here. There is nothing wrong with using consumer grade lenses, and there is nothing wrong with a lens design falling a little short. But this is a $1,100 plastic lens (with glass elements) which in my opinion is just as overpriced as the 16-80mm DX zoom that falls into about the same price point. In my mind, the story might be completely different if the list price were closer to $600, but it's not.
Both of the lenses I've mentioned are, in fact, available used for $600-750. My concern, though, is that these lenses may have been pretty heavily used. Internal wear on plastic parts could put them near the point of failure.
In the final analysis, you have to decide. One strategy that I've used when considering purchase of something that carries mixed reviews is to look around to see how many used versions of a particular lens are listed for sale. If the list is long, that serves as a warning flag there there are a whole lot of them on the market that for some reason people did not want any more. Also...look carefully at the most negative reviews. Try to determine if the problems described are real, imagined, or just user error. If real, consider whether they are important to you. Then decide.
Good luck as you move forward with your choice.