The original CQR anchor has lead in the tip of the plow to aid in setting.
No it doesn't.
What about the relative strengths of the various materials? I looked at stainless anchors and chains once, and my recollection is that stainless, while very pretty to look at, is actually weaker than the run-of-the mill galvanized steel most anchors are made of. So we went with galvanized...deciding this was a case where function was more important than aesthetics. I have no idea about the comparative strength of bronze. And I may be mistaken about stainless vs. galvanized, too. Any metallurgists out there?
Stainless is typically a little weaker than regular steel compared on a like-for-like basis. However it's very expensive, with the practical result that many stainless versions of steel things actually use inferior metals to cut costs. Anchors is a good example. You won't see good quality stainless in the average chandlery, stock is too expensive to hold and doesn't turn over, and that shiny stainless Bruce knock-off sitting on the floor priced at less than the galvanized genuine Bruce used to sell for is a dangerous piece of junk.
However with reputable manufacturers there is nothing wrong with stainless, and it has obvious advantages over galvanized steel if you're prepared to pay for it. Stainless can be very strong; where the steel Rocna uses an 800 grade shank (about three times stronger than mild steel), the stainless version must use something similar - a 2205 grade high tensile stainless is used. This is extremely expensive steel!
I had planned on getting the Rocna until Steve Brodie at the factory sent to me a photo, I am just to vain.K
Unfortunately things that work well are not always pretty - look at anything used in the military. Rocna is more concerned about how the anchor works than some romantic notion of traditionalism, which will do little to protect your boat when the anchor needs to do its job
A bronze anchor is a bit 18th century for my thinking. I'd suspect a CQR knock-off in bronze was mostly intended to be ornamental and I'd be very suspicious of the tensile strength of the alloy let alone the design quality.