I agree, neon tetra disease is very rare, i keep 9 neons in with guppies and i have never seen the desiese. If by chance you do get it, Protizin clames it can cure it. (not sure if this is true, I dident think there was a cure).
They are a good fish which are colourful and active, and will add a neon blue and red effect to your aquarium. They are peaceful and eat anything, i mean anything. They do like shade from lights, if they have no shade their brilliant colours are lost. You can use plants or decorations E.G. rocks.
A word or warning, they seem to stop schooling as much as they get older.
A bit off topic but worth mentioning , i wouldent get cardinals if i were you, as they are sensitive to change in enviroment, for example PH and tempature. Also they are usualy wild caught, as they are nearly impossable to breed in captivity. They are genraly less hardy than the neons and are in need of more care.
Thanks and hope this helps!
AQUAKING