KNOF,
I used to use the leather holders before...
I also didn't like the fact that it left a strong leather scent on my wrappers...
As far as the cigar wrapper taking on the flavor or smell of the leather I am not really sure on a physics level what happens but in my mind all I smelled and tasted was the leather so who cared!!
I now use a cannister travel humidor that had a cedar lined interior and my cigars are all beautiful now when I pull them from my traveller...
Jose