I'd say they're much more true to size. The Ribelle Run felt like an anomaly, as its sizing doesn't seem correlate with any of the others in Scarpa's running collection. The Spin ST is also a lot lower volume too.
The Spin ST are definitely mud monsters. That boost foam isn’t overly cushioned though, so they’re definitely a soft terrain specialist. I wouldn’t like to be doing too much rocky terrain with them, as you can feel every stone beneath them. Either that or I’m being soft. I’ll try to get the review written up in the new year once they’ve had a couple more months of use.
