I’ve had my rigid SS round Glentress red, Innerleithen and part way round the black at GT, as well as doing a few loops in the Pentlands etc. It’s also had a trip to Lee Quarry in the past, which was fine apart from grinding up the hill with one gear. To be honest, it is not as much fun as the full sus, but it is handy for when the other bike is in need of repair, or I want to save on the cleaning and maintenance.
Riding rigid at trail centres is fine, as we generally stop for a chat after most sections, which gives my hands a chance to recover from the death grip.
It works particularly well on trail centres, which tend to be a bit smoother and the climbs are more manageable on the SS than more natural trails.