I collect cacti since 10 years. My favorite cacti are mexican, and since 3 years (I think) also Mammillaria.
But I prefer only small Mammillaria with big flowers. This is better for the greenhouse, more space
I only have some Mammillaria, not a big collection like other cactifriends here on board.
When I`m not at work or in the greenhouse, I like to travel (also Mexico haha).
Some Mammillaria in greenhouse
Mammillaria picta, near Tula (TAM), 2013