F2FS fine, but hoping for BTRFS
My usage is much more minimalistic than perhaps yours, but I recently completely formatted by GT-P5110 to F2FS (apart from my microsd) and while I have yet to do any comparative benchmarking I have also not experienced any problems on Codename Lungo with AGNI's kernel. Phoronix has done plenty of benchmarking between EXT4 and F2FS with each providing benefits over the other is certain areas. To be honest, I would much rather get BTRFS onto Android and play with that. I have used it extensively on Arch Linux and it can be dialed in very well for flash and further can provide compression and will eventually support in-band deduplication.