Navarchus are beautiful fish, and not one of the larger pomacanthids which is a point in their favor. Caribbean Angels, with the exception of the Rock Beauty are BIG BIG fish: one main reason for my going with the angels I have. Many people regard P Navarchus as fragile. I will say this, mine is something of a drama queen: on the two occasions where I have had to move it, it lay on its side during acclimation, giving me a panic attack! When first acquired, I gave it a fresh water dip prior to quarantine, and that was another "dramatic" moment. But it eats everything: Mysis, Algae Sheets, Spectrum Pellets, Angel Formula, Krill, Squid, Lifeline Herbivore, even flakes. I have nick-named it "Pudge" as a testament to its appetite.
My advice is to wait for a great specimen (both in terms of beauty and health), have plenty of live rock, feed a varied diet including lots of green food and angel formula and keep your water quality high. Should do fine. Mine is pretty reclusive, but amiable with everything else in the tank, and that includes two tangs and an Annularis Angel.
Despite the Naso Tang
's many good points they also get quite large and what others have said regarding activity level should be taken to heart where tangs are concerned. In my experience tangs are much more active than angels and spend a lot of time swimming and swimming fast. The angels seem fine swimming in and out among the rockwork. In a sense, a nice big pile of live rock is like "habitat enrichment" for an angel. Tangs like to graze on live rock, too, but when they swim they seem to prefer open unobstructed space.
These are only my observations of my own fish, so take them for what they're worth. . .each person's tank has a slightly different dynamic, so read as many accounts from other owners, too.