Seat type desireability is very much a matter of personal preference. I have flown on several different versions of the "lie slanted" seats (AF, AA, NW, KE), and I find all of them inferior to the old Delta BE seats. I have trouble sleeping in them because my body keeps sliding down the slant. I sleep better in the old BE seats.

Of course, the true lie-flats are superior to all of the above.