Light output. The E1 is rated at a maximum light output of 12 lumens; our test sample measured 11 and change. In terms of real-world scenarios, this is enough light for a 25" diagonal image in a typical brightly-lit room or perhaps a 40" diagonal with very good light control--say, indirect light from a window on a cloudy day. You could certainly use the E1 in brighter environs, but be aware that contrast will drop to nothing and text will become quite difficult to read.
LED lamp. The chief advantage of an LED lamp is virtually unlimited lamp life; 20,000 hours is a very, very long time. Since there is no dust filter in the E1 and the lamp is not meant to be replaced, this means the projector has no required maintenance aside from occasionally changing the batteries.
Stereo speakers. The E1 features dual 0.5W speakers. These tiny little speakers do start to sound tinny if you crank the volume to full blast, but at around 75% volume they sound bright and clear, if a little lacking in the bass department. For a small group of friends, it's enough that you'll be able to hear what's happening, which is really all that can be asked of such a tiny projector. A group of 6-8 people is about the largest with which one could show off this projector, and a group of this size will be served perfectly by the onboard speakers.
Highly portable. The big draw of a projector like the E1 is portability. With batteries installed, the E1 weighs only 0.3 pounds, or a smidge under five ounces. That's less than a good-sized apple, for reference. At only 1" depth by 2.4" width by 4.5" length, it is a pocket projector that will actually fit in your pocket. The E1 comes with a small faux-leather carrying pouch to keep it from being scratched up in your bag or pocket; this bag adds minimal bulk.
AA batteries. The E1's use of AA batteries instead of an internal battery pack is a double-edged sword. On the one hand, this forces you to buy new batteries every time you run out of juice; on the other, this allows you to recharge instantly any time you like, and all you need is a new set of AA batteries--which can be obtained anywhere for relatively little money. One thing that everyone will be happy about is that a charge lasts just under four hours, even when watching video the whole time with the sound at full blast. That's impressive battery life for a pico projector.
Included accessories. Plenty of pico projectors plug their portable prowess, but when it comes time to deliver the goods, they require a bevy of "optional" accessories to get the most out of them. Not so with the E1. Included are a full set of cables - Composite video and USB being the most important - as well as the international power adapter and carrying pouch. Also included is a miniature tripod; the E1 has a tripod socket on its bottom panel so it can be positioned easily, no matter the situation.
Onboard storage. The E1 includes a gigabyte of onboard memory, perfect for storing photos and videos you want to share. Simply plug the E1 into your computer via USB and it will show up as a removable drive, as would any USB flash drive you are already familiar with. Drag and drop your files to the E1, then eject when you have finished copying. That's it--you're done. The projector's menu system will direct you to choose either photos or video, and from there you simply scroll through the list and pick what you'd like to see. A slideshow mode is available for photos, while a playlist function can be enabled for video.
If a gigabyte is not enough, the E1 sports an SD card slot, allowing for additional storage. SD cards range from 1GB to 32GB and are small enough that several can be carried without adding significantly to the weight or bulk of the projector. The SD card slot is located under the battery cover.