When comparing elementary vs Flat Remix, the Slant community recommends Flat Remix for most people. In the question“What are the best icon sets for Unix-like desktops?” Flat Remix is ranked 2nd while elementary is ranked 8th. The most important reason people chose Flat Remix is:
When an icon isn't provided by the theme, you cannot really spot it as this theme is quite close of the default with still a subtle and classy look and feel.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Good contrast
Icons have a dark border around plus a subtle shadow at the bottom and hilight on the top to improve the contrast with the background.
Pro Nice cohabitation with default icons
When an icon isn't provided by the theme, you cannot really spot it as this theme is quite close of the default with still a subtle and classy look and feel.
Pro Under GNU GPL3
Based copyleft license.
Pro Very large collection
This set contains icons for many file types that are ignored by other icon sets.
Pro Flat but with some depth
Cons
Con Under GNU GPL3
Limited use elsewhere.