Been using this for a while with the latest PA and I thought I'd report my findings.
1. No noticeable performance gain myself. Perhaps slightly faster when installing an app but that's it.
2. Few force closes of background processes, but nothing making the phone unusable.
3. Force closes and slow-downs when running Simpsons Tapped Out. Probably because a lot of small data is loaded at once.
4. Some kernels claim f2fs support but don't work. Sometimes you can't boot, sometimes decrypted storage comes up. This can be fixed sometimes by installing modified kernel here first and then the said kernel, but sometimes that doesn't work. - I suspect this is more to do with the kernels than f2fs itself and has been explained earlier in this thread.
5. Sometimes wifi was turning itself off. Not sure why was this happening though.
It probably could be used daily if you wanted too, but for me I'll revert back to ext4. You have to remember that everything gets tested using ext4, so if you get problems in games or apps which read a lot of data you know what's to blame.
thanks for giving me the chance to test