Degree of Portability
How portable do you want your ideal compressor to be? Portable mini projectors today are classified as either palm-top or pico.
Palm-top projectors are portable enough to be carried around when they are needed, while pico projectors are smaller generally resemble a smartphone in size and weight.
If you have to carry a portable projector with you every single day of the week, the pico projector is your best bet. If you would rather leave your laptop behind, invest in Palm-top projectors that are able to read files directly from a USB flash drive.
Second, what type of resolution do you want and how bright does the projector have to be? The standard resolution for most portable projectors is 800x600, but there are models that would offer you more choices. Keep in mind, though, that most portable projectors rarely have HD as the native resolution.
While brightness is no doubt an important factor, similarly crucial is the lightning conditions of the area where you intend to use your projector. That is, a project will low brightness will do well in a library than in a well-lit conference room.
Mini projectors top out at 250 lumens, but there are portable projectors on the higher end of the price scale that boasts of more than 2500 lumens.
How do you want to operate your projector? If you hate the hassle of dealing with wires, go wireless. However, if you think that the wireless model is too expensive - which they generally are - there are projectors out there who offer remote-control operability
Noise output is also one essential factor to consider. If you hate the noise of cooling fans, choose a unit that has the lowest decibel values, approximately 36 dB or less.