One doesn't go into a film with this obvious theme... and judge it by his/her own bias and pre-conceived dogma. It's obvious in advance the writers and directors are going to put their own slant on this-- and it's not even possible to match the beliefs of every individual who watches it.
This is a morality tale that goes beyond the common concepts of heaven / purgatory / death / whatever. It's fanciful, not factual. That should be a given. Those who review this poorly because "That's not how it is"... really have no idea "how it is". They haven't personally experienced any of this. Faith and beliefs don't even come into the picture. It's a fantasy movie, nothing more. It doesn't intend to present heaven as a bright room someone walks into, nor does it present purgatory / hell in any fashion. It's a movie about personal choices.
The thing to take away here are the points of conversation between two men, starting with the truck driver at the beginning and following through all the way to the end. The viewer doesn't have to agree with everything presented or said, or even agree with any of it. It's just put out there for consideration. The film has a beginning, a climax, and an ending, all tied together. At least there are no major contradictions or plot holes, which is something in itself.
They don't have to explain everything. They don't have to have a reason for everything. This isn't presented as a realistic concept. It's just a story. It's not scripture, it's not reality; it's pure fantasy with a lot of points made about love, hate, apathy, control, and other human emotions, strengths, and frailties. If anything, it's a study about humanity.
Does it all stick together and work? Not necessarily. Could it have been done better? Yes... and has been, by other films. The theme has also been done worse, in other films. This isn't a movie about how people go to heaven. It's a movie about choices people make and why they make them.
I give this a mediocre 5 stars because I didn't find it particularly well-done from a cinematic standpoint. It was mildly interesting, but the characters were very 2-dimensional. That above all hurt the film, as the audience never really identifies with anyone. There isn't enough told about the main character to make him sympathetic. The same holds true for the caretaker; a bit is told about his back story, but not enough to really draw us in. That's the primary flaw of the entire film; it's too slow-burning without any real emotion and grit in the presentation.
It's just a story. If the viewer takes away a bit of philosophy in the process, that's fine. Some people may love it. Others may dislike it because it doesn't agree with their personal beliefs. If that's the case, they should have never started watching it in the first place. In the end, you take away from this what you choose to take away from it-- which is the main lesson overall.