Never saw this the first time around. The current name is Austrocylindropuntia subulata, but everybody knows it as Opuntia s. It is native high in the Andes, where people grow it on top of masonry walls to block intruders. Both crested and normal forms should take full sun almost anywhere in the US if adapted gradually. Birdbrain posted a photo of the normal form
here.
The normal form becomes a very large plant, to perhaps 20 feet / 6 meters. It has beautiful, cupped flowers at the tips of mature stems, mostly in the range of reddish orange to light orange. I haven't seen the crested form produce flowers, and it will never be nearly as large as the normal form. But it may produce normal growths. Be sure to clip them off or they will take over the plant. They can be rooted easily, and the plant can be kept to a reasonable size by pruning. Normal forms may bloom when a foot or so / 30cm tall.
Monstrose and crested succulents often have abnormal root systems, as well. They tend to be much smaller than root systems on normal plants. They are more prone to rot. Making sure they dry between waterings is important. Many people to put them into a very shallow pot so they dry faster.
The Euphorbia is a very easy-to-grow plant, from Madagascar. It too can easily be adapted to full sun in the Atlantic, coastal California or the Midwest. It burns in hot desert sun. It grows in full sun in Madagascar but at relatively high elevation.
Pay attention to mealy bugs. A lot of succulents nowadays come from the vendor with mealy bugs, which may hide at the roots of cacti. The plants may have been sprayed with something that controls the populations but does not kill all of them. Crested plants are particularly prone to die from root mealy bugs. I wish I did not have to, but I now put imidacloprid granules in the soil of all crested and monstrose plants. They are unlikely to flower so I am not as worried about harming bees.