Clowns are extremely easy. Most anemones need expert care. Clown host anemones need intense light and excellent water conditions, and I would try to dissuade anyone who has not successfully kept a reef aquarium from trying one.
Incredibly hard if you consider the fact that it is rare to keep an anemone alive for very long. And by long i mean more than 1-2 years. Considering the fact that many anemones live well over a hundred years in the wild and that most die in aquariums after 1 year at most I would say that it is very hard.
Some people do manage to get them to live for 6 years, maybe even 8 or so at home but that is like saying you raised a goldfish for 4 years and it was long lived.
Another part of the problem is that there is very little proper info on them and by that I mean true scientific information on their proper requirements.
You shoudl also realize that clowns do perfectly fine without them. My brother's clown host with his brain coral. I have even heard of clowns hosting with powerheads and flower pots.
Clowns will host with anything, flower pots, powerheads, and fake decorations (there are some life like plastic Anemones that look almost like the real thing that clowns can host with)