Coats are another confusing issues. Many dogs don't really come in to their coat until they are adults. Knowing the approximate age of the dog will help here.
Aussies bred for conformation tend to have very heavy coats while working aussies have a lot less. Dogs in the south often have less coat than northern dogs and of course winter coats are heavier than summer ones. Show Aussies will have the densest, longest coats and smooth dogs are nearly unheard of (but not impossible) in English Shepherds and Aussies - but after that really all bets are off and each of the breeds could trade fur suits with the other and no one would know better.