Premium Economy offers more leg room, wider seat, and a little more of an upscale food menu. That's pretty much it. If these aren't really a priority for you, then I'd say pick Economy, especially with that price difference. For me personally, Premium Economy is worth it solely for the leg room since I am very tall. I flew LOT Economy in 2018 and I did not have a good experience since the passenger in front of me was basically in my lap since I'm 6'5". It was the longest 9 hours of my life lol
No. This is an additional charge. When you book through the LOT website, there is an option to add lounge access in Warsaw. It was $30 per person at the time of filming. You will not have lounge access if you do not select this option.