The problem with DREAMLAND: AREA 51 as a documentary is that it's entirely one-sided with no attempt at balance. If you wanted to see a biased story in which a bunch of believers explain why they think there are secret aliens and alien spacecraft hidden by the American government, then this is the documentary for you. If, however, you'd like to hear the other side of the story from those who refute these claims, you'd be better off checking elsewhere.
This British-made effort is clearly a labour of love for writer/director/narrator Bruce Burgess, whose aim is to reveal the secrets about Area 51. There are a lot of interviews with respected individuals in the UFOlogy field, and these are quite entertaining, although I could have done without the lacklustre recreations which they always seem to throw into these documentaries. The bits where Burgess and his crew actually visit Area 51 and its environs are the best parts, very suspenseful, but there are far too few of them.