Integrated lug, integrated rail, ‘on the shelf’ availability of shouldered prefits, and stock/chassis compatibility are the most important “features” for me. Lone Peak Fuzion would be my choice if buying today. Maybe a Terminus Zeus if there was one stocked, but I wouldn’t preorder, and I’m biased to have had good experiences with Lone Peaks.
Impacts are very popular, and I’m on the edge of grabbing one, but I prefer not to have trigger hangers. I have a Ruckus that’s been good, but I wouldn’t buy post Defiance buy-out. I’m sure Kelbly, Bat, etc are good, but I want to be able to hop on the internets and buy a prefit from whoever I want.
Depending on what features you want, there’s likely at least a couple actions to chose from that will be good.
LP Fuzion is an excellent choice for a modern pushfeed, 90* action that accepts prefits.