I went with one of the Faux Leather (Plastic) versions since I read that they don't sag or deteriorate as much. So far, one years worth the bag works very well. From 5 feet you cannot tell the difference. I have mounted mine with tie wraps because I was deciding whether I was going to continue with it. They work great as well. When I need to remove the bag for any service or serious cleaning I just cut and replace the ties.
Very easy, cheap although not elegant these types of bags are water resistant and don't sag. I went the same route with a Fork Mounted Tool Bag.
I do like Genuine Leather but practicality won out. Works for me.
Barrier

 

I used the deadcreek mount on my wife's Iron, nice piece. Badg&customs makes a good sized solo bag, which is what she has. The standard leather option is nice but does lose shape when empty, the thicker options are quite stiff. I have one of their bags that fits behind the shock on mine.