Others have covered the Airstream negatives pretty well so I won't rehash other than to say that I think they are super cool inside and out. But for us they aren't liveable. Too cramped and antiseptic feeling inside. Very small beds.
That said, the difference between an AirStream and a standard TT is kind of like the difference between a standard TT and a hybrid trailer. Very different ways to RV, and very different opinions on why people like or don't like them.
Since you are used to a normal box trailer, my question is, have you been able to spend a bit of time inside of it, or another one to see how it feels to you? When you do, just imagine how it will be to camp in. You might love it the same way we love our hybrid (its our second one!)