I use aeoniums as ground cover in a number of spots for the simple reason that they are so easy to propagate. Just take a rosette and stick it in the ground and you have a new plant.They do best in bright areas or filtered sun. But they are not fool proof in that they do need some regular water. They are not cactus! The picture above is a spot that they are quite happy in, a neglected corner with just the right amount of sun and water.
This picture is a spot they are not too happy with, along the curb in the front yard. My garden helper put them in on his own when the creeping thyme wasn't doing so well. Naturally they can't be walked on so maybe not a great choice next to where people park and get out of their cars. But the main problem is not enough water in this spot. There are sprinklers here, but the soil is so thin and sloped that it just won't seep into the ground and these guys are thirsty (but they are still creating offspring I notice). They ball up and turn red when not happy. I am planning on replacing them with dymondia in the fall or next spring. Not my favorite groundcover as far as looks go, but I guess you can't beat it for being tough and drought tolerant. Almost anything will be an improvement over this!