Roll axis/fox. Fireball too. But axis and fox are far superior to Elka. Unless you get into there stage 5 stuff.
I have a jannsenn (fireball) front end with axis shocks. Standard travel.
Roll design stock length swinger with a Baldwin rebuilt rear.
I've never seen the JDperformance in person but from the pics it looked good.
You want all handling parts to work well with each other. So a good stem, bars, rear axle, correct offset wheels, brakes, tires, and a few other small things.
I could go on all day about suspension and set up. Ergonomics is the best way to ride all day. A lot of people over look that stuff.