I have two Versipacks, one "S" type Fatboy and one Jumbo E.D.C..
The Fatboy I have had for about one year, and the Jumbo now for the last six months or so.
These bags are top shelf. They have been tossed around, dropped, kicked, sat on, stepped on, hung, crammed full of dumb crap and carried everyday.
One thing I will suggest is to go with the Jumbo if you are going the over the shoulder route, and get it for the opposite side that you carry your gun (if right handed, get the "S" type). The Jumbo will have a large enough rear pocket to carry a fullsize gun (I often carry my 1911 in that pouch when I am wearing my XD and vice versa). The rear pocket on the Fatboy is just a little too small for the full size frame. It would work great for a revolver or mid to compact/sub-compact handgun. The main compartment on both bags is huge, and has two pockets in it for smaller loose items. The external pockets are handy for a lot of uses.
I have to clean my bag out about once a week to get rid of the silly junk that finds its way into it from day to day. Makes for a great little range pouch as well. It is such a versatile bag that you will find many uses for it.
DO get the universal holster that they offer as well. For ten bucks it is well worth it. I need to get another one.
I am going to make the Fatboy a small necessities kit that I can throw into the vehicle for trips or emergencies.