Kodachrome has had mixed reviews. The NY Times was particularly disparaging without really explaining why, other than noting a certain irony of a movie celebrating analogue physical media being shown on Netflix. I find that a little sad given that the movie is based on this original article in the same paper. And it's a great movie!
You could reasonably complain that it's flawed and predicable, even frustrating in places. It's not ground-breaking or particularly original. It could be a little longer and go deeper. Personally I loved it. For the characters, the themes, the backdrop. A road movie with Ed Harris, photography and an old Saab. It was never likely I'd hate it. If you have Netflix, give it a try.