I've got a bone to pick with the whole F2FS saga. It's touted as having superioer random write performance.

Back when the hype started people were largely relying a benchmark app that was bugged. And nobody even seemed to notice it. Example here:

http://forum.xda-developers.com/showthread.php?t=2697069

Look at the Androbench results.

Ext4 Random Write: 1.71MB/s  
F2FS Random Write: 297.97MB/s  

In otherwords 174% improvement. The raw number alone put in desktop class SSD transfer speeds. In short the benchmark was bugged.

I noticed it myself when I was tinkering with F2FS back then. Nobody ever seemed to point out that Androbench was reporting incorrect results. The app was silently fixed some time later but not after the F2FS hype train was in full steam.

Look through the benchmarks posted from around the same time and you'll find more examples of this.

In addition when formatting a partition a discard is done on the storage device. So it must be factored in that people reporting amazing improvement could have been due the discard. That is around the time people starting getting Android 4.3 and 4.4 which is when Google added automatic TRIM scheduling.

I'm not saying that it's better or worse than any other file system in whatever way. Just that it fell wayside to the hype and hysteria.