You'll need more ANSI (the way it's measured) brightness for well lit rooms.

• Data Projectors are often used for sports events, they offer a easy to set up projector that you can move from room to room.

 See also Home Theatre Projectors

Home Theater or Cinema projectors are wasted if you have a lot of light in the room.

The only way you can really see the difference is to cut down the ambient light. Then, especially in dark scenes a "proper" home cinema projector will run rings around most data projectors. Turn the lights way up and the opposite happens but subtle details will be lost.

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Got a lot of light? You need a "Data" projector.

Check out the New Epson EB U32 Projector Review, it's got the lot.

If you have a brightly lit room you need a bright projector, it overcomes the ambient brightness in the room. 
Brightness (higher ANSI lumens) fools the eye to perceive black when in fact the black is simply less white than the very bright whites.

As a general rule Data projectors are brighter but less subtle in a dark room. 

 You can buy a DATA projector for the board room and use it in the lounge room. 

 Don't buy a Home Cinema projector and try to use it in a well lit board room or commercial application.