Well-made film sounds ok to me --- To me, anyway, it carries a slightly different connotation.
"It was a well-directed film" -- The directing was great, but maybe the acting or set design or costuming, etc, wasn �t so great.
"It was a well-acted film" -- the actors were fantastic, but the rest was just so-so.
"it was a well-made film" -- all of the elements were high quality and I have very positive impressions about all elements of the movie.
If you are looking for a way to use the comparative or superlative -- I�d say "It�s the best-made film I�ve ever seen." -- because to use a comparative or superlative you need some reference to the things it is being compared to.
I wouldn�t say it is a better-made film, usually. That seems a bit odd. I might say that "Movie X was made better than Movie Z". But if I want to show that Movie Y is best, I�d say something like, "Movie Y is the best-made war movie I�ve ever seen." to emphasize the quality of actually producing the product.
"Movie Y is the best war movie I�ve ever seen." -- implies you just think it gave you the best experience of any war movie you have seen in all your life.
Hope this helps.