The Benq MS517 has a maximum resolution of SVGA (800x600). That's 39% less resolution than a XGA (1024x768) multimedia projector, which is the most common resolution.
A SVGA (800x600) native projector resolution is actually the worst resolution amongst all projectors that have been around for around the same time as the MS517.
Amongst similar types of projector the best resolution is WXGA (1280x800).
We think you might also be interested in some of the alternative data projectors that have a resolution of SVGA (800x600) currently available including cheaper projectors such as the MS512, or the MS504 (£482.22) both from Benq or the Acer X11.
If the resolution of this data projector is not high enough for you then you might want to look at the Benq MX522 (XGA (1024x768 and higher rated) and higher rated); or the Benq MX505 (XGA (1024x768 and cheaper) and cheaper), or the Optoma DX346 (£421.06) (XGA (1024x768 and cheaper) and cheaper).