I find a lot of the time it might be £350 in economy Vs. £1300 in PE.
An example here where I would pay the little bit extra:
End of Feb, LHR-JFK
Basic Economy: £470
Economy: £583
PE: £855
CW: £3293
Definitely wouldn't pay at least 6-8x the Economy price for CW, but PE is the sweet spot.