I love the camera on the 6+ but I have the damnedest time getting consistently good shots. On some days every photo will be crystal clear, but the next day 80% of my shots will have the smudgy watercolor look.
Much depends on lighting. Low light can push the camera's limits and also yield slow shutter speeds where good lighting uses lower ISO and higher shuitter speeds.
Not saying that good images can not be had in lower light, it just takes some practice