in my experience the Rocna has excellent holding power. I weathered the Medicane in Greece last October with this Anchor (45+ kn winds for several hours) and also used it on a couple of occasion with similar wind speeds.
It sets quite fast within 1-2 m of the drop point. It has some problems on weed, but so has nearly every other anchor.
Yes, I suggested that a stainless steel chain has a much better tendency to stow itself because it is more "slick". But as you pointed out, stainles steel is not stainless steel. While in cold waters like Northern Europe you may do ok with AISI 316 (1.4401) quality for a while (1.4571 would be better if you anchor often), in the Med and in tropical regions the only material you can use for any prolonged perios without corrosion problems is 1.4462 Chrome Duplex.
Unfortunately it has a price tag 4 times the one of galvanized steel - which did keep me away from it so far ;)