Our church is wanting one to mount from the ceiling to project hymns and whatnot.. And they asked me to "find out what we need". I don't know much about them. If I go to some online retailer and search "most popular" would that be a good start? I assume I will need a wireless adapter of some sort to communicate to the projector from the soundboard area.
I don't know how you feel about emailing a stranger for advice, but our church, nhbconeida.org, uses a setup like that. The email for the guy who makes it happen is
greg@scottcounty.net. If you email him, he could give you the specifics on what he uses.