I DO NOT recommend the Uncle Mike's pack.
The Uncle Mike's design requires you to grab the front of the pack and pull it outward, away from you.
This "breaks" a snap at each side of the pocket and tears open the Velcro seal.
The problem is, the Mike's is made of slick nylon, there is no "handle" or tab to grasp, and it's difficult to maintain your grip.
What often happens is, as you attempt to tear open the pocket, your hand slips off, and you fumble the draw.
It works better if you grab with both hands, but this is very awkward, and slows you down also.
There are a good number of packs on the market, and the better ones DON'T look like gun carriers.
I can recommend the Blackhawk 5-5-10, and the Eagle Industries of Fenton, Missouri which is a close copy.
I like the Blackhawk because it's a more refined pack than most on the market, isn't huge, and doesn't scream "GUN".
Most packs are basically just standard fanny packs, with a gun pocket added to the design.
The Blackhawk was designed from the get go as a gun "holster" not a gun "carrier".
In other words, IT'S FAST, and secure.
It also has a more refined and sturdy construction, smoother and more rounded buckles, rubber coated zipper pulls, spare magazine loops, and loops for attaching a "rip cord" handle for fast opening.
Unlike the Velcro-seal models, there's no chance of the gun working it's way through the Velcro and exposing the gun, or worse, dropping it out onto the floor.
The only "minus" is that you need to supply your own "rip cord" handle, which is easily made from some nylon cord and a toggle or ball handle of some sort.
The best thing about the fanny pack is, it's a complete carry system.
You have your gun, spare ammo, CCW ID, wallet, checkbook, keys, and cell phone in one package.
This helps eliminate the chance of running down to the local Stop 'N Rob WITHOUT your gun.
Since everything is in one package and the pack attach's to you so quickly, you're less likely to leave the gun at home.