When making a buying decision for projectors, there are always 2 things to 
consider: features and price. You then weight both elements and determine which brand and model has the features that you want, at the price that you want. Once you have the information at end, the clear winner will surface. Your buying decision then becomes a piece of cake.
There are several features you may wish to consider when buying projectors. The most important one is the brightness of the projector. Lumens.
The brightness of a projector is measured in lumens. Lumens are displayed as 1000 ANSI, 1500 ANSI, 2000 ANSI and so on. The higher the value, the brighter the projector. If you need a small projector to make presentations in a small meeting room, a 1000 or 1500 lumens projector will be ideal. However, if you are going to stand in front of several thousand people, you need a more powerful projector. Consider buying a 3000 lumens projector.
Contrast ratio.
The contrast value is another feature to consider. If the projector features a higher contrast ratio (e.g. 10000:1), it means that the projected images will be very sharp. A 10000:1 is a very high end projector. Most projectors fall within the range of 1000:1 to 3000:1. A 3000:1 contrast ratio is good enough for a group of several hundred people.
Compatibility.
Most modern projectors are compatible with display monitors. For example, you should be able to connect the projector to a TV (including HDTV), or a computer.
Resolution.
Resolution goes in tandem with the power of the projector. More powerful projectors are able to display images or videos at higher resolution. A higher resolution display means that the images are sharper, and you can project bigger images on to the same display area.
Lamp.
The lamp is the only component of the projector that requires regular replacement. For instance, a lamp may last for 2000 hours. But if you wish to prolong the life of the lamp, you can always choose to use the lamp in eco-mode (if its available). Using a lamp in eco-mode may lengthen the life span of a lamp by as much as 50%.
Warranty.
Almost all projector manufacturers offer up to 3 years warranty. This means that you do not have to worry about reliability issues. If there is anything wrong with the projectors within the first 3 years, just send it back the service center for repairs.
After considering all the above features, you must then take the price into consideration. The higher end models can cost as much as 2 to 3 times more than low end models. Low end models are meant for very small groups of approximately 5 to 10 people. Mid range models are ideal for 10 to 100 people. Anything above a hundred people, you may need a high end model.
