Horsehide or cowhide

Horsehide repelles water better (tighter fibers). That's it

 

Cow strictly because horse milk sucks.

 

I do believe kodiak is correct...

Here is a real good explaination site... http://www.holsters.org/which.htm

 

I agree with Kodiak and, other than the obvious bad guy trying to harm you, water/moisture is your Glocks worst enemy

They do like a light amount of lubricant but other than that staying dry keeps them always ready to work

 

Hot, humid climate: Horsehide
Not humid, moderate climate: Cowhide