I use both rollers and pot. Rollers for eyebrows, upper lip and also when waxing my own legs. You have to have several roller cartridges on the go though, to ensure the wax in them is always hot enough. If you keep using just one, it isn't in the heater/holder long enough to warm up again, to have the wax flowing freely and not have it dragging on the skin/hair.
I then use the pot of lavender wax for everything else.
I don't do intimate waxing, but would have thought pot and spatula is best for that.