What does he mean, harder to fix?
Spraying clear is one of the most difficult things you can do with paint and it's real easy to get runs in it unless you are in a WELL LIT spray booth.
Single stage will give you a VERY durable finish and will look more like the factory paint. Two stage is going to look "wet" it will be so glossy.
Either one is an excellent finish, just pick your shine.
