Aluminum doped surfaces can have a very high gloss, depending on who painted it. On many civil aircraft it is quite a high quality surface. On military planes it may be slightly less so, but still pretty shiny. I use Testors gloss silver. I really recommend paint, rather than Alclad, because it is, and looks like, a paint.
One reason it is used a lot is because aluminum paint stops UV damage to fabric, so it was used as an undercoat before spraying on the final color coat. But, hey, since the aluminum is really all you need, why not leave it just aluminum color? I know several folks refinishing aircraft that went that route for that reason.