Bought the bike new. Shock was leaking from day one. Shop said, it might be normal, give it some time and see if it goes away. The leak never went away, but the damping adjustments did recently (after approx 600 miles, less than a year), and now with seemingly no damping the ride and action of the shock are better than when it was new with the damping turned all the way down. Air pressure / sag were set to spec for rider weight.
In my 30 years of experience riding all sorts of bikes, coil shocks have always been better than air. I had hoped that things had improved with air shocks in the past few years that I got away from full suspension, but sadly, I just haven't been impressed with this one.
Clearance issues with a shock that has an external res are primarily because I like to run a water bottle, and it's fairly close to the shock.
Not finding anything about linkage design or ratio, but wheel travel / shock travel gives a 2.63:1 ratio, if that means anything to anyone.
The bike: E-STREAM EVO AM 3 (S MAG)