The best parts of LENNONYC were the little snippets of John just being the funny, articulate, weird and brilliant icon we grew up adoring. Also enjoyable were the interviews with the producer and musicians he worked with in the years and months before his death.
The film was obviously tightly controlled by Yoko Ono and so has a feel of censorship to it. It seems to be the story of Yoko Ono and her husband John and their life in the 70's and the brief period in 1980 before and after John's death. Yoko's narcissism is palpable.
It's an interesting resource if used as one fraction of the spectrum of Lennon's life. If you're really interested in John Lennon read what his son Julian has to say, May Pang's memories of her time with him ( some nice little interviews with Pang in the film though) and as many other diverse sources as you can find.
The interviews with Yoko are cringe provoking. It is not possible to respect someone who removed the Lennon name from their record label within weeks of his death (later restored) or someone who profits from images of John's glasses covered in his blood from the night of his murder. Who does that? My anti-Yoko bias obviously coloured my perspective of this documentary.
Often annoying, the film is still interesting as a narrow view of a flawed genius and loveable rogue.