The number alone is incomplete
A small file may describe a short programme, a heavily compressed film or only part of a larger release. Size does not establish completeness, resolution, language tracks or picture quality.
Longer films need a different comparison
Compare the duration alongside the size offered by your viewing application. A number that seems comfortable for one episode may imply a different picture compromise for a long movie.
Readability before a higher label
Inspect motion, subtitles and darker scenes. A 1080p label is not a guarantee that fine detail remains intact. Choose from the actual supported options rather than chasing one file-size phrase.
Downloads on this site
No 300MB movie archive is supplied here. Use Movie4U to identify a production, then use offline viewing in a supported application when that offer includes it.
A practical travel choice
Select the spoken language and subtitles you need, finish the supported download and test it before leaving. A smaller edition that you can comfortably follow is more useful than a size target chosen without seeing the film.