I think the criticism with exception handling is that it's a bad idea to silently pass errors up the stack by default. This encourages deferring your problems to outer scopes, at which point you often aren't sure precisely what the error means (or you may not have known to expect it at all).

With Go, although you can pass error codes up the stack if you want, you have to do it explicitly. This forces you to think twice before doing so.

This is a key difference: exception handling subtly encourages ignoring errors and letting outer scopes handle them, while error codes force you to deal with your problems within the immediate scope, and then decide what to do from there explicitly.