Thru-hiker used to carry pl1 bonded to a scrim later to stabilize it. This eliminated the need to quilt it every 3”, but I think the clo/oz including the scrim was no better than apex.
Pl1 also drapes around you closer, and compresses much smaller than apex, but doesn't last nearly as long.
I think of apex as warmer, slightly lighter, and slightly more compressible than older synthetic insulation like polarguard 3d. I think of pl1 as a safer/moisture-proof version of 550 down, that only lasts a season or two, and is slightly less compressible, and slightly heavier.
Apex also lofts up significantly faster, and more fully, after being compressed in your pack all day.