I don't think the 150 has a recess in the dropout. I have a bike with a 150 rear wheel and it can be tricky to get the axle in at times. The 157 dropouts have a recess where the endcaps sit in.

 

Correct. Same hubs other than endcaps, but 157 fits bikes that have the 3.5mm recesses in the dropouts, so you can drop the wheel into the slots and it's easier to insert the axle.

I had a 150 bikes since 2014, and it's no big deal to hold the wheel and jiggle it a bit while starting the axle in. But 157 would be nice to have.

 

So I’ve never owned a bike with 157 rear, but my understanding is that there are two different ones: the 157 DH spacing which gives you flange spacing a little wider than 142 but flanges are the same distance from center so that the wheel isn’t dished; the other is super boost which is asymmetric and flanges are as far apart as possible.

150 hubs are basically a 142 with more space on the non-drive side to keep the flanges the same distance from center.

 

"Superboost" is just a marketing term Pivot created for nothing new as best I can tell. Wide-spaced, asymmetrical 150/157 hubs have been available for many years.

I've tried to find the actual specs on the few hubs that are being marketed as "Superboost" to compare them to the wide 150 hubs that already existed, but have not been able to find them thus far. I want to find out if my old Stan's 3.30 HD 150 hub purchased in 2014 is a "Superboost" hub!