SPOILER ALERT ( as always )
Interstellar is a widely disputed film, with true sci-fi fans loving it, and realists hating it.
And this also depends on what lens you are viewing Interstellar through. For entertainment value I thought it was pretty good. As a work of storytelling, however, I thought that it was superb. And as a science-fiction movie, I thought it was brilliant. But as a film I thought it had some problems that took it just below being perfect. Although some of this does have to do with my bias going into the film. I knew that it was obviously a sci-fi film, depicting space travel and other fictional events. However as there seem to be two different types of sci-fi, the realistic and unrealistic, this was where I was thrown. What started out as a gritty and realistic sci-fi, through the course of its 2 hour and 49-minute runtime gradually became an unrealistic sci-fi with moments where I found myself almost cringing.
Hence my problems with the film.
CRAFTSMANSHIP: Interstellar is a superbly crafted film. The sound design, the visual effects, the set design, the practical effects, and almost everything else involved in the production are top notch. As an example of a well-crafted work in the medium of film, Interstellar is a masterpiece.