Hoya rigidifolia is probably a Hoya that would mostly appeal to serious collectors. The foliage is not the most interesting and with the flowers only lasting a day, there would never be a big demand for this plant. I found it somewhat difficult to cultivate, but others might find it easier. While I can’t give it an enthusiastic recommendation, if you are given one, or find it for a bargain price, it might be worth giving it a go.