How can a movie about the making of a movie be good? The answer is, have a real-life person be so crazy that making a movie about their life will just work. The Disaster Artists has that and one thing that all other "based on true events" movies wish they had, authenticity. Not only is the movie over the top and enjoyable to watch, its because that is how it was in real life. You can't make up the events that transpired and the over the top nature of the story really draws people in.
There is a certain finesse to the way the story was told. Everyone loves to make fun of The Room, the movie that this one is based around. This really puts people in a certain mindset on how you would see the people behind that movie. This movie tries to break that preconception by showing you that the people behind the movie are not one-note characters. They have feeling and dreams that can be broken over time.
The Disaster Artist is most importantly about a friendship and the people in it. Their wants and desires in life bring them together, stronger than it can pull them apart. It humanizes a person who, to be frank, seems unredeemable when you first hear about him. This is probably the best movie that utilizes meta-culture at its best.
I would recommend seeing this movie. It doesn't have to be in a theater and you don't need to have seen The Room before watching it either. The true-life story is so crazy that anyone can enjoy it.