The vast majority of people would say the differential in cost of anything more than economy is not worth it.
I think the answer will be related to how many hours a year you spend at 35000 foot in a tin can, and how many nights away from home you spend.
If someone offered you £1200 in cash to downgrade from WTP to WT would you take it?
If someone offered you £3000 in cash to downgrade from CW to WT, would you take it?