Overall Picture Quality
All considered, I have to say I really like the picture of the BenQ W1500. The color is very good out of the box, and great once calibrated (try our settings). Dark shadow detail is excellent, and generally image noises are not a problem, other than the general DLP tendency for more visible mosquito noise.
The only real complaint has to be black levels. Now if you are watching the W1070 is a less than ideal room, with some intentional ambient light, then great black level performance is not going to be noticed, even if the projector was capable of it. Still, that won't always be the case. If you have that less than great room, but will watch those movies with dark scenes when you can fully darken your room, then the loss of great blacks is noticeable. And folks that's why this is a home entertainment projector. True, I did say that the W1070 works well in a dedicated theater, but that's a $900 street priced projector. Here we seem to be $1500 and up, and at that kind of price, there are competing projectors that are definitely better at the black levels. The W1500 should, in other words, have a dynamic iris, but it doesn't. BenQ, as I have mentioned, has a good excuse: The BenQ W7000 isn't much more money, and has far superior black level performance, because it really is more of a home theater projector.
So basically the W1500 is great on non-dark scenes, but is barely respectable at black levels for serious movie viewing of very dark scenes. Personally, I would own the W7000 over the W1500, all else being equal.