I'm not sure about the crocodile situation but there are several operations in the southern United States that farm alligator. That's all I buy--American Alligator. So it is a renewable resource, not in any way endangered.
Side by side the most significant difference is that crocodile has a pore at the top of each tile....sometimes hard to see. And crocodile tends to have smaller tiles for the same size skins. But if you choose small skins to work with--a 30 cm skin will make one full cut oxford--the difference may not be noticeable.
On the other hand, if you get a dinosaur of a croc and cut from the throat it is sometimes indistinguishable (for the inexperienced eye) from sea turtle. Which, in turn, increases the demand for sea turtle. Even if only marginally.
As for wear properties, alligator is much, much denser than calf skin. In the last 30 years or so alligator and crocodile have been tanned with more modern chemicals and they are comparatively much softer than the old Bombe' finished skins. That said, even with a razor sharp knife it can be difficult to cut some of the tiles that verge into the back or in the tail. So, a shoe made with tail leather, for instance, will not crease as finely or conform to the foot as easily as a shoe made with belly or throat. That can affect comfort.
On the other hand any leather that develops deep and fine creases or, more importantly, has a texture that creates extreme variations in surface will collect dirt and dust and this is where the shoe will deteriorate first. In many localities, a certain percentage of dirt is actually comprised of fine volcanic rock or glass--the High Desert of Central Oregon is one such place.
Alligator is very scuff resistant and very durable. I don't have any hard evidence but I would guess that the newer tannages of alligator will out last calfskin four to one, all other things (like cleaning and conditionaing) being equal.
A 30cm skin--measured across the belly--will run roughly $300.00-$500.00 wholesale. For a full cut oxford you would need two. That should give you a starting figure for pricing shoes made with alligator. Of course that's the "St. James Av." quality--the best belly cut with the smallest tiles.
Although I'm an otherwise fairly conservative dresser, I have a weakness for alligator and crocodile shoes and accessories. I have several pair, but found that I don't have many occasions where I think they are "appropriate". So, I recently sold these Allen Edmonds on B&S:
and I'm currently offering this pair of Nettletons:
Even though I still have another couple of pairs in my closet, I hope I don't eventually regret thinning the herd with these sales.
While I'm usually not into overly exotic leathers, I find crocodile and alligator leather shoes to be that wonderful little indulgence, a foil to over-restraint. That said, where I live you may occasionally find less tasteful people walking around in white/cream/greyish off-white imitation hornback leather slip-ons, which are probably one of the worst displays of ostentation the "metro" or "modern man" has brought society. Of course, this is all IMO.