Merely adequate video quality. Despite having a higher resolution than the MS517, the MW519's video quality is arguably a little worse overall, largely because of more obvious noise showing in more scenes. On the plus side, I didn't see any issues worth mention with skin tones and shadow detail, and I didn't any posterization in scenes that tend to cause the problem.
Another potential issue, as with any DLP projector, is rainbow artifacts. I didn't see enough to be an issue with data images, but with video, I saw them more often than with most projectors, including the MS517. I also saw them in scenes that I rarely see them in with other projectors. If you see rainbow artifacts easily and find them bothersome, or worry that someone in your audience might, any video you use with the MW519 is best limited to short clips.
The MW519 can connect directly to a Blu-ray player or other video device for 3D as with the MS517, but it also suffers from the same shortcomings in image quality, with minor posterization in skin tones, 3D-related judder, and a tendency for dark areas to take on a glossy look. The 3D image was also noticeably dimmer than a 2D image at any given size. And as with the MS517 also, the projector works only with 144Hz DLP-Link glasses, which means you can't use older, 120Hz glasses.
Low volume audio. Another shortcoming the MW519 shares with the MS517 is its 2W speaker delivering too low a volume to be useful. If you need audio, you'll want to use an external sound system.
Ultimately, the MW519 succeeds as a low-cost, light-weight and portable, 1280x800 data projector. There's nothing particularly outstanding about it, with the possible exception of the low price, but it can certainly handle its basic job well enough to be useable, with more than acceptable data image quality, a longer than typical lamp life, and nearly as good portability as LED projectors with lower brightness and, in some cases, higher prices.
The limited 3D support and low volume audio count as minor issues at worst, given that the MW519 shares both with most inexpensive projectors. Potentially more important is the relatively low video quality, with the frequent rainbow artifacts an issue for anyone who considers rainbow artifacts a problem.
Compared directly with the MS517, the MW519's issues with video quality make it the less desirable choice if you want a projector for video. As a data projector, however, it has the edge, thanks to its higher resolution. If you need that higher resolution, and are looking for an inexpensive projector for a conference room or classroom, a brighter alternative to a 500-lumen LED projector for portable use, or both, the MW519 is certainly more than a reasonable choice.