The highest resolution of the Benq MS521 is SVGA (800x600). That's 39% less resolution than the most frequently found native projector resolution of XGA (1024x768).
A SVGA (800x600) native projector resolution is in fact the worst resolution across all 13000:1 contrast ratio multimedia projectors that are a comparable age to the MS521.
A WXGA (1280x800) native projector resolution is the best resolution across similar types of projector.
It may also be worth considering one of the other projectors that have a resolution of SVGA (800x600) currently available including the MS512, or the MS504 ($308.99) both from Benq or the Acer X11 which has a better Rating.
If the resolution of this data projector is too low for you then you might also want to consider the DX346 (XGA (1024x768)), or the DX325 (XGA (1024x768)) both from Optoma or the Benq MX505 (XGA (1024x768)) which also has a higher rating.