I prefer the look and enhanced comfort of sheepskin girths.
That particular one, since it's removable, will be even easier to wash. I have two synthetic sheepskin schooling girths, and those I just let the sweat dry, then brush it off with a stiff brush. If it's super dirty, I'll get a water hose after it, and let it air dry. So not to dramatic to clean.
I don't have a leather one yet, so I'm not sure what cleaning the sheepskin would be like then.... But then again, that ones removable... I like it.
"You're just as sane as I am."~Luna Lovegood.