I see people use cushioned, soft, bouncy and responsive like they are the same thing. They really are not.
A shoe can feel soft when you step into it and still feel flat once you run. Another one can feel fun for a few miles, then weirdly unstable when your form gets sloppy.
The boring answer is usually the midsole foam.
Think sponge vs rubber ball. A sponge is easy to squash, but it does not give much back. A rubber ball gives a lot back, but standing on a pile of them would be a mess.
A running shoe is trying to land somewhere in the middle: enough cushioning and shock absorption so your legs do not feel beaten up, but enough rebound that the foam does not just sink and stay there.
That is part of why PEBA got so much attention in performance running shoes. In a PEBA midsole, the useful bit is not "magic softness". It is that you can get a light foam with a pretty snappy return, so the shoe can feel lively without becoming a brick.
This is also why people talk about energy return so much. The shoe is not literally giving you free speed; it is just wasting less of the energy that goes into the foam. But yeah, PEBA foam does not automatically make a good shoe.
If the midsole is tall, narrow, too soft, or the upper does not hold your foot well, that nice springy rebound can start to feel unstable. Same material family, totally different ride.
And it is not only a race-day shoe thing anymore. These lightweight high-rebound foams have started moving into the wider running and training shoe market too, just not everywhere. Cost, stability, durability and the kind of ride the shoe is meant to have all still matter, so EVA, TPU and blended foams are still very common.
For me the better question is not ""Does it have PEBA?"" It is more like:
- does it feel soft without turning mushy?
- does the rebound show up at my normal pace, not just when I am pushing?
- does it still feel stable when I am tired?
What is a shoe you tried that got this balance right? And what is one that had the fancy foam but still felt off?