1. An instantaneous judgment.
His appearance is now awful.
He looks awful wearing that hat.
2. Observation of a more long-lasting, yet transient, state.
His appearance has been (regularly) awful [these days / lately].
He's been in chemotherapy this month, and he is looking awful because of it.
I find it hard not to add "these days" to the second one. The
second is almost a substitute for the equivalent present perfect form.
CJ