Not great, but watchable. If you didn't read the book or watch the documentary on Lady Gucci, you may not be able to follow the story. The script was a disappointment, the real-life story had great potential for theater, but because the film had no main character, the story became choppy and schizophrenic.
Lady GaGa plays an unlikable character and her performance was like a good tuba player who can only play one note. Unfortunately GaGa's one-note intensity became tedious to watch.
Adam Driver was much more watchable. Had the script been written using either Driver or GaGa's character as the main, it would have been a much better production. As it was, the ending was a huge let down. The most interesting part of the story was how Lady Gucci was finally caught and her subsequent trial, but none of that was in the film. The ending will leave you severely disappointed.
Bottom line: save your money. It's not worth going to the movies to see. It's only a tolerable film if you don't have to pay for it.