The EPV DarkStar 9 is one of three screens in this review that offer a maximally wide viewing angle, the others being the Da-Lite Parallax and the DNP Supernova. For all practical purposes you can view any of these screens from any angle without serious degradation of the image.
So what are the differences between them? First, the DarkStar 9 offers a contrast advantage against the Da-lite and DNP. In the first contrast test with side light only, the DarkStar 9 registered 20:1 compared to 17:1 for the Da-lite and 16:1 for the DNP. That difference in contrast is certainly visible. But beyond that, the DarkStar 9's advantage in contrast grew when the ceiling floods were turned on -- in that test the DarkStar9 didn't lose much contrast at all, reading 17:1 by holding an excellent black level (second only to the SI Black Diamond in this test). Meanwhile the Da-lite and DNP both fell to 12:1. So if you want the highest contrast of the super-wide viewing angle screens, the DarkStar9 should be on your short list.
The second difference is that the DarkStar9 manifests an extremely low level of texture artifacts. It is not perfectly free of artifacts as the Da-lite and DNP are, but it shows noticeably less texture than any of the other screens in this review. As far as trade-offs go, our guess is that most viewers would accept the occasional minor texture in order to gain the contrast advantage of the DarkStar 9.
In terms of vertical half angles, the DarkStar9, the Da-lite and DNP all measured a rather restrictive 18 degrees -- not the worst in this review, but not far from it. So, no difference between the three in this regard. Similarly, these three screens are the least bright among the nine when viewed at center position, which is the typical price you pay for maximum wide angle performance.
In short, the Elite EPV DarkStar 9 is definitely competitive in its niche, with the key advantage being the best contrast performance in high ambient light of all the ALR screens that offer maximally wide viewing angles.