For The Love Of Port

One of the "other" Portuguese fortified wines, of which I am quite fond.

Does anyone have knowledge of whether these wines hold up well in a cellar?

For instance Madeira will last a very long time, while Tawny Port is best enjoyed within a couple years of bottling. (Yes, I know there is some debate on the tawny)

But what about Moscatel de Setúbal? Should I stock up on these when I find them - to enjoy years later? Or will they decline like a tawny can?
I'm not expecting them to improve, but I see these so rarely in the U.S. that it would be nice to stock up when I encounter them.

Thank you!

I've of two minds. I've had some vintage wines from JM Fonseca from the early twentieth century which held up well for 15-20 years. I've had multiple bottles of their 25 year old (no longer produced) with 20 or so years which were distinctly tired.