It's also the biggest and heaviest at 6.3 x 1.3 x 4.0 in. and 1.1 lb. And it's one of the two covered here that doesn't have a battery, requiring you to plug in a 9.12 oz. power brick.
The Qumi Q5 projects up to 500 lumens and has a contrast ratio of 10,000:1, which is important in a living room or hotel room where you might not be able to totally control the darkness. It feels very solidly built, with smooth sides, rounded corners and a glossy plastic top. It even comes in different colors: The review unit was navy blue, but you can also get it in black, white, yellow or red.
Vivitek Qumi Q5
The projector's smooth lines aren't otherwise marred by the controls, which consist of six touch-sensitive buttons on the top: one for selecting the current option, one for stepping back up through the menus and four for navigating the choices on any particular screen. One sign of the Qumi's build quality is the tight feel of the focus wheel on the side. Of all the units I looked at, it was by far the easiest to focus precisely.
My only complaint is that, although the buttons light up when you're using them, they go dark very quickly -- you have to brush your hands over them to get them to light up again, and it's easy to accidentally trigger something you didn't intend to. I remedied the problem by sticking to the included remote.
Lots of options
The Qumi Q5 offers a variety of source options. There is an HDMI port for projecting content from, say, a tablet or a DVD player. It also has a "universal I/O" connector with a VGA adapter for displaying data from a PC and a 3.5mm AV-in port with a composite video/stereo audio adapter.
You can also project files from a connected USB drive or from the Qumi Q5's 4GB of internal memory. (You copy files by connecting the device to a computer via USB.) You can use the buttons on top of the unit to project a menu of file types such as photos, movies and office documents; selecting one brings up a list of corresponding files. The Office Viewer selection can display native Microsoft Word, Excel and PowerPoint as well as PDF files; and the video, audio and image selections handle a good assortment of common file types, including H.264 and MPEG-4 video; MPEG, AAC and WMA audio; and JPEG, BMP and PNG images.
There's also a Web browser option: With an optional Wi-Fi dongle ($99.99), the Q5 can connect to a wireless network -- handy if your presentation is on Google Docs or if you want to stream a movie.