I’ve ran stans rims since before they became fashionable, from about 2005. Mostly flows, but some crests in the last couple of years.
IMO, they are softer than the Maxtal alloy that mavic use. They accumulate rock marks and scuffs more easily and do seem a little more prone to flat spots. Like Peter Poddy, I tend to keep my rims for a good while, and I have found that eyeleted rims seem to give more mileage. Presently I’m using Sun-ringle black flags that seem to offer similar benefits to Stans, but have eyelets.
Despite being softer Stan notubes rims are lighter for a comparable strength, have a wider profile and they make tubelessing so very easy. This was especially true in the early days of tubeless when pretty much it was Stans notubes or UST. You’d save 100 to 150g going with stans over Mavic.
I’ve never once encountered the fabled tight tyre syndrome that seems so frequently reported on here, but then, I’m like the thumb guy.