each one has his specific and unique style. All of them do have a very good quality and do manufacture it using old tools and techniques. No aggressive chemicals are used so the straps don’t smell strange or a harmful for the skin. Not cheap though but worth it.
I have tested 2 of them as well in sea salt water successfully. Here are my favorite brands. I hope it’s ok to share it including my view about them:
-Mays Berlin: nice old looking straps with a rather consistent and steady Patina .
-Corrigia : more Vintage Look. Patina is Not so steady and consistent which I like a lot.
-Kostas straps: just ordered 2 but haven’t got them yet. He does have old leather. So they are probably almost the closest you can get towards original.
All of the 3 are cool pretty competent. They know what they are talking about and very trustful.
Corrigia and Mays do have blue version.
I hope I could help . Enjoy the journey of finding the next strap or better the next strapS