In Cuba there's not a lot of models available so you get a list of those then review/read reviews.
I'd start with http://www.cnet.com/topics/tvs/best-tvs/projectors/ if you are in NA.
What is the best projector for under 4k for a smallish (12 by 12 room)? I am building a new home and leaving a much bigger theater room that had a Runco in. Is there anything I can by at this price for a room of this to come close to the picture I am used to?