IMo & IME; if you can get an idol to eat (that's the tough part); then they are very easy to keep. Like Kirk said, I did have one for about 10 years and, when I first got it, thought I was going to lose it. It finally ate some freshly opened clam and would eat anything from then on. I do have one in QT now and it eats anything. I made sure it was eating before I bought it (online). I know these fish aren't for everyone; but they are plentiful and require the usual "delicate" species stuff: pristine water, large tank (150 gal. min.), no bullies (they like to just be left alone and never bother other fish), a varied diet with lots of sponge, vitamin supplements, and some luck. I sure think an experienced hobbiest who can provide for this fish can try one without being put on a guilt trip. This is one fish I would never buy unless it came from Hawaii. I also agree with Kirk on the Achilles: once acclimated, they thrive.
Also, IMO, I think the smaller you get "delicate" fish (with some exceptions), the better. It's easier to get a fish eating what you offer before he's established a real strict diet in the wild. This also applies to most large Angels.