I have a single pivot like the Starling.
Very linear is accurate. Can get it to be somewhat progressive if the forward shock mount was lower, such as if you ran a shorter length shock to fit better, but it's so slight that it don't matter. If it were mounted to the top tube, it'd be somewhat regressive, but it'd be more accurate to call it linear still.
You don't need progressivity to stop it from blowing through its travel. You want progressivity if you want it to blow through travel, such as wanting it to be plush running a lot of sag. I see no problem running coil, but going to need a firmer/racier spring rate, which gets chassis stability (geo retention) and efficiency over cushiness.
It has an imperceptibly similar level of pedal feedback compared to a majority of other susp like this Yeti. The Yeti, and some VPP, have a slightly difference in that it drops off harsh pedal feedback for the last 30% of travel. I suppose this little bit matters when you're after fractions of a second to win races.
It preserves geometry under braking, meaning it better balances out the forward rotation that causes the fork to dive, just like the Yeti. In other words, it more completely cancels out brake jack, which is the tendency for the rear end to extend under braking (hence why it's called anti-rise, or brake squat).
Single pivots have a more rearward axle path. They can be more precise, suffering from less torsion and tail wag (fewer pivots, less play, between pivot and rear axle). They're more hardcore than horst links. GG argued there was no benefit with Horst Link, and that they could simply mimic their single pivot kinematics with it. There's a world of difference between a Knolly 4x4 (or Liteville horst link) and a GG horst link. Not so much difference between GG's horst link, Switch Infinity, and Starling single pivot.
Tantrum Missing Link is one of the few innovative linkage designs. It happens to be regressive and needs a progressive shock (DVO Topaz is a good choice), but it's the only one that stands out from the crowd. In contrast, the vast majority behave similarly. Not much difference among single pivots like Trek, Evil, Marin, Cotic, etc. and 4 bars like CBF, VPP, etc.
The draw to the Starling design is its chassis stiffnesss characteristics. It has a forgiving springiness. It's carries its weight really well--the steel frame does a lot to negate pedal feedback.