My $0.02: DL hard product is better, so easier to sleep going east. AF soft product is better, so nicer experience for daytime flight going west.
Overall I was disappointed with the PE service on DL all around. Same meal as economy, have to walk to the back to use the lav, drinks service was limited to one drink only, overheard a flight attendant tell a pax that they din’t have vodka in the cart and didn’t have time to go look elsewhere, etc etc… essentially Delta has not told the flight attendants that the P in PE stands for “premium”.