theres a slight difference but saying which is better out of the two is marginal at best
To me, on good quality headphones, the difference between 128kbps and FLAC, is disgustingly obvious, I avoid listening to 128Kbps wherever possible. It really sounds horrible compared to FLAC or 320Kbps, I am not exaggerating, it sounds horrible in comparison, once you know the issues with the compression, you will notice them all of the time.