Spiridon - to answer your question about horsehide, I favor it because:
1. Weight. I like to have some weight to my jacket. Heavy does not equate to stronger, but horsehide can be both for sure.
2. Strength. I like to feel as if the jacket will offer me some protection as well. No matter how strong leather is, if it is thin you might not rip it, but you will feel things through it. Lay on a pile of gravel with a light lambskin and a heavier horsehide and see which feels more protective.
3. Break-in. The lighter goatskins and lambskins are very comfortable, but my feeling is that if we were the same size and you wore my 2 year old lambskin jacket it would be comfortable on you due as well to the nature of the leather. The same with the lighter goatskins. Take my heavier, broken-in horsehide and wear it. It won't feel right on
you because the horsehides take on the shape of the wearer. Every one I have owned has anyways. It truly becomes your jacket. In fact, while on a hanger, the arms of the jacket have taken on the bend of my elbow.
4. Resistance to the elements. Goat and horsehide are both pretty good in the rain. Most give the edge to goat, but I disagree.
5. Appearance. On the average the goatskin is pebblier in appearance. Horsehide seems to develop a grain.
This jacket looks the same on the hanger as it does when I am wearing it. It is heavy, but deceivingly comfortable. It feels protective like a suit of armor, yet it moves in the right places so it is comfortable...
Of course, this is all my opinion, but the jacket that meets all the requirements I want (plus fits right) wins my vote as my favorite jacket.