Ranked in these QuestionsQuestion Ranking
Pro Few permissions
It asks only for Storage permissions. No other things are required.
The app takes only a few seconds to download, as its size is only about 1.5 MB to download and installed (on MIUI) takes only ~6 MB full size.
Pro Open Source
OI File Manager is available for free under the Apache License 2.0.
Pro ZIP file extraction support
OI File Manager supports extracting ZIP files.
Con No additional features (suite)
No other features such as networking connections, junk flies cleaner, built-in media player/viewer/editor. But that might be a pro, since nothing else is asked for this app permission.
At this moment I'm writing, it was updated last in 2017.
Con Ugly UI
The GUI is old and deprecated. But what would you expect for such a small app?