One of the main qualities I assessed was brightness, though that's more significant in a conference room at lunchtime than it would be in a small, dark room. Brightness is measured in lumens, a metric set by the American National Standards Institute (ANSI) to determine the average intensity of a projected image -- a higher number means a brighter image. These projectors are rated between 85 and 500 lumens; as such, they throw less light on a wall than does a 60-watt incandescent bulb (about 800 lumens). However, in the same way a 10-lumen keychain flashlight is bright enough for finding your way in a dark room, these projectors all provided enough light for our test conditions.
I also concentrated on the clarity of the projected text and the saturation of the colors in the photographs, as well as the clarity and contrast in the projected movie. All of these are improved by increased brightness as well as higher resolution.
Four out of the five projectors display their menus on the wall -- none of them have built-in screens. The iPico requires an iPhone app, which shows your choices on the phone's screen.
One other thing: All the units have audio-out jacks for headphones or external speakers. Use them. The projectors have built-in speakers, but they're laptop-quality at best. Since they all have fans going as well, you need something more than what's built in to rise above the background noise.
Finally, all these projectors involve some tradeoffs, such as whether the unit has a battery or you need to be within reach of an outlet. Similarly, some really are "pocket sized," while others require at least a small carrying case. But once your movie is running, the images look fine.
I've looked at these in descending order of brightness (in other words, the lumens rating), from the feature-filled Qumi Q5 to the iPhone add-on iPico. But although there are many differences between these devices, there really isn't a bad projector in the bunch.
5 pocket projectors
$650 (list), $544 - $702 (retail)
With a list price of $650, the Qumi Q5 is the most expensive projector in this roundup. However, it also tops the specs chart -- it projects the brightest and highest-contrast image and supports up to 1600 x 1200 resolution (native is 1280 x 800).