I've travelled BA premium economy (they called it World Travellers Plus) as I booked it almost the last minute and the price of standard economy was almost as expensive as PE class, so I might as well booked that. I have to say the seats were more comfortable and spacious, but everything else really was more or less the same as standard economy. For example, they handed out a dinner menu with starter, main courses and dessert, but everything was just served in the same tray with a tiny box of starter and dessert each. Service wasn't really much different from what I got in standard ecomony either.
Just wonder what your experience is and would you pay extra to travel BA premium economy?