Premium economy has been widespread outside the US for about 15 years and is a relatively standardised product across most airlines that offer it. Usually 19-20 inch wide seats and 37-38 inches pitch and slightly better food/amenities. It is distinct from products generically referred to as economy plus that just offer better legroom.

On any airline, including the Oneworkd ones, you’ll find it similar to Delta’s recently introduced PE product that it brands as Premium select. One airline where the PE is particularly good is Japan Airlines.

Ok, I’ll bite.

I’ve flown BA’s premium economy product on the 777. Decent product. Good legroom. Soft product was fair.
This was about 8 years ago, so I don’t know if it’s changed much.

On DL, I mainly fly D1 long haul international and haven’t flown in another cabin long haul since 2011.

I would suggest looking at trip reports and reviews for OW premium economy flights. That way you can see the product and draw your own conclusions.

DL seem to have done a good job with Premium Select branding, and persuading people that it is something different / better than regular Premium Economy. This is the second or third similar thread I’ve seen recently.

i actually haven’t flown PS yet, but I’ve done PE in Virgin Atlantic and op-uped into it on Air France. Those experiences lead me to think there’s a pretty wide range in experience!
From what I’ve seen, PS won’t be as nice as Virgin, but it won’t have anybody wishing they were back in normal economy, which some people say about the Air France pod seats.

The BA hard product isn’t terrible. A bit dated, but comfortable - as comfortable (IMO) as JL. As with BA J, though, the soft product is weak, especially on the food front.

I disagree, the physical seat space of premium economy is remarkably consistent across carriers. You get like 38-40” of pitch, some type of footrest, and maybe 18-19” of width, plus additional separation between seats with thicker armrests with a small cocktail table. I think the only outlier is Air France with it’s fixed shell seat. Now, padding, the shape of the seat, accessability to power/IFE can vary, although some of that can be highly subjective.
I disagree that some are just Economy plus and others business minus, when business is almost entirely flat beds these days. No one in PE will think they’re thisclose to being in a flat bed. JMHO.

PE seats on VS are 21 inches wide, a discernible difference.

Note that the PS equivalent hard product is likely to be dependent on aircraft type for those carriers that have installed it on various generations of their long haul fleets, just like D1 seating is indeed dependent on aircraft type (although with D1 suites being a very new product, there aren't many differences between the A350 and 777 versions).