This one I got as a bonus plant with an order and it has exploded with flowers. The flowers seem self fertile and there seem to be a lot of fruit developing. I try to give it a little shade in the middle of the day but that doesn't always happen. It seems a vigorous grower.
When I was first trying to identify this, before the grower got back to me with the name, I thought it looked a lot like the pictures I found for Rebutia vulpina. I see some treat vulpina and rubiginosa as synonyms of Rebutia spegazziniana. I'll stick with the grower's name but it's nice to see I was at least in the right taxonomic neighborhood.