Conclusion: For a short throw projector, the Acer S5201M is a solid performer both in brightness and sharpness. While this alone can be matched by other projectors on the market, the S5201M separates itself from the pack by including interactive ability at a very low price. While I had some issues with the interactive software, I believe that with a little getting used to, it would be more than adequate for most uses.
Pros: Good brightness, Sharp image with any resolution, Interactive pen works well, If mounted, lamp can be changed without unmounting the projector, No dust filter to clean or replace, Can be projected on a variety of different colored surfaces, Can present from USB drive, 3D ready
Cons: Primary colors are dark in the Bright mode, DLP rainbow artifacts are noticeable with video, Whiteboard software could use improvement