Light output. Pico projectors, traditionally, are not very bright. The E3 is among the brightest at 50 lumens. Our test sample measures a respectable 47 lumens. This allows the E3 to be used at larger image sizes and in brighter environments than most pico projectors. Image sizes can be made larger when viewing text documents or slideshows than when watching video, since these simpler documents are higher in contrast than most video. The E3 has a small selection of image modes, though they seemed to have little effect on color balance or lumen output. We seldom saw a reason to take the E3 out of its default mode.
Onboard media player. The E3's onboard media player is fairly robust, especially compared to its predecessor. For one, it can accept a wide variety of video formats, and it played all of those formats smoothly and without stuttering or frame rate loss. Second, it had no trouble compressing large images to fit in its native 848x480 pixel matrix, which is especially important given the projector's onboard SD card slot. This encourages people to take their SD cards directly from their cameras and put them in the E3, so the projector is likely to deal with some very high-resolution files. Heck, even cell phone cameras these days are up to five megapixels in some cases, with point-and-shoots going up to 12 without breaking a sweat. With the E3, you don't need to spend time resizing your images before you can show them off.
Connectivity. On the E3, the primary input is an SD card slot, which you'll use to load media onto the projector before use. There's also about 100 megabytes of internal memory and a USB port so you can use USB flash drives, but you'll need a micro-USB male to full-size USB female adapter which is not included with the projector. There is also a special composite A/V breakout cable to connect with a DVD player, iPod, or other such device. The included driver software lets you project from your computer over USB, though this software is limited to computers running Microsoft Windows.
Format compatibility. The E3 supports many common file formats, such as mp3 for music, jpeg for photos, and mpeg, AVI, and mpeg-4 for video. Not all video files are created equal, though, and often two files labeled "AVI" can have very different internal characteristics that make one playable and the other useless. If you ever plan to use the E3 to present video in any sort of business capacity, make sure to test your files beforehand. The bundled software also provides a way to convert Powerpoint slideshows and PDF documents into a format that the E3 can understand, as these files cannot be displayed natively.
Touch keypad. With a projector this small, adjusting the controls tends to throw the body of the projector around, which has a tendency to mess up image focus. This gets annoying very quickly. The E3 has a touchpad interface, which means you can access the menu at a light touch instead of a physical button press. The downside is that the controls can be accidentally nudged whenever you're near the projector, as the pad is very sensitive.
Sound. The onboard speaker is not very large or very powerful, and turning the volume up too high introduced some distortion that made dialogue hard to hear. However, keeping the volume at or below 70% of maximum yields perfectly acceptable sound, especially for a projector this small. The projector also has a headphone jack, so you can keep the sound to yourself while you watch a movie. The E3 did not introduce any audio artifacts when using the headphone circuit, either.
Warranty. The E3 has a one-year warranty. This is standard for most pico projectors; a few have two-year warranties, but these are the exception to the rule.
LED light source. The advantage of LEDs is that they last much longer than traditional metal halide lamps. While the E3's lamp life has not been published, similar projectors are expected to last anywhere between 10,000 and 30,000 hours.