I had a DA18-250mm that I replaced by a DA18-270mm. I am a prime lens shooter mostly, but I value highly the convenience of the DA18-2XX mm. I have also a DA18-135mm, mostly because of its WR feature.
The DA18-270mm is, like the DA18-250mm, the perfect all-around lens in my opinion. It is small, compact, relatively light weight and very versatile. I loved my DA18-250mm and I love my DA18-270mm. I considered alternatives like the
Sigma 18-250mm and Sigma 18-300mm. In each case, the weight and size was an issue for me. I often bushwalk with my camera and lens, and I want something light to carry. In addiition, the Sigma 18-300mm was pricier than the DA18-270mm at the time of my purchase.
If I compare side-by-side the DA18-250mm and DA18-270mm, I am very impressed by the AF of the DA18-270mm, its speed, reasonable accuracy and it is almost silent. IMHO, the AF is a major improvement over the DA18-250mm.
Similarly I have the DA18-135mm. Both my wife and I use love the DA18-135mm. But the DA18-270mm is more versatile in my opinion.
In summary, I would rate this lens as an excellent all-around zoom lens. My main criticism is the lack of WR. Off course the IQ of DA18-270mm is well below that of most prime lenses. But that is not the point because one should compare apples and apples, and oranges and oranges.
Hope that the comment will help.