I usually ask a smith what works best for him- from which can he coax the highest performance- and then discuss which are the most important aspects to you.

Personally I would not consider nickel alloyed damascus to be high performance so it'd be off my list.

There a zillions of vintage simple steel razors and we all know how much knifemaker's etc love to tout the stailess_es so if I were getting my first custom razor-and I would be- then I'd probably try to get one that was as difficult to sharpen as possible really. some kind of abrasion resistant really hard stainless