Sony VPL-VW70: Bottom Line Sharpness
As I've stated before, the great thing about "average sharpness" 1080p projectors is that they really look very sharp. There's not one current 1080p projector that I would reject, based on the softness of its image. That doesn't mean one can't appreciate the slight additional sharpness of those that can do better.
If you are obsessed with sharpness - or at least very concerned, consider that you are more likely to notice the sharpness differences between, say the VW70, and the InFocus IN83, which we consider one of the sharpest, when viewing all digital source material, such as live sports on HDTV, or those great travelogues, general interest and scientific channels, such as Discovery HD, Travel HD, etc., than when watching movies originally shot of film. With film, you already have built in artifacts - the grain of the film, which inherently have a softening effect.
Bottom line: While you can find a few projectors, that side-by-side are visually sharper, the differences are not great, and, at least in my opinion, only a minor consideration in your final projector selection.