I beleive LOT flies a 787 lie flat ex JFK.
Warsaw airport is nice, and if you have a few extra hours can go to the old cemetery/ghetto memorial.
I was once in Israel when some Gaza conflict flared up, with rockets hitting TLV area. Many airlines cancelled flights, I was only able to find a flight out in J on LOT TLV-WAW-YYZ-LGA. TLV-WAW was fake J which was as expected. I had a long layover in WAW, really liked the lounge and the shower. WAW-YYZ was my first time on a 787. Nothing to write home about, pretty lousy IFE, and soft product was definitely not something to write home about. YYZ bring a horrible airport IMHO, didn't really leave me with good impressions (except for LOT lounge at WAW).
All the above not withstanding, I need to be able to stretch out in order to sleep (which is important on long-haul). I'm OK with angle flat, but I doubt a PE seat will enable proper rest for me.