A couple of years ago I did a review of the PACA body armor, which was worn in a carrier that was covered with MOLLE attachment points. When I did that review I had covered the vest with STRIKE pouches from BlackHawk. The STRIKE system is essentially an upgraded version of the MOLLE system. Since the President of BlackHawk, Mike Noell, started BlackHawk because of an equipment failure with his issued kit, it's a safe bet that he, and his company will always look for ways to improve upon the military issue items. STRIKE did it from the get go, but now they've evolved it again. Let's take a look.
The first thing I should address is the evolution: BlackHawk's STRIKE system no longer requires you to sit and fight with webbing and reinforced nylon strips as you try to weave your pouches onto your vest or carrier system. Instead, they've invented what they call Speed Clips. Made from their proprietary exceptionally strong carbon-fiber composite, the Speed Clips are available in four colors: Black, Coyote Tan, OD Green and Foliage Green. The Speed Clips also come in four lengths to fit the pouch you're attaching. Lengths run from 3 inches to 9 inches. To use the Speed Clips, you simply align the pouch on your vest or carrier and start pushing the Speed Clip through, weaving the web and pouch as you go. Because of the stiffness of the Speed Clip, and the fact that it's not sewn to the pouch on one end, this makes mounting pouches much faster. At both ends of the Speed Clip are integrated hooks that grasp and hold the webbing. This is typical BlackHawk: a simple and expedient solution to reduce the time necessary building or reconfiguring your vest system.
That said, let's recognize that vests get built to address many needs. What the combat operator in Mosul might need right now, the SWAT cop in Arkansas might not. The whole point of being able to configure and build your own vest is to make it match your needs. BlackHawk manufactures a wide variety of pouches that can be combined in any way that will fit on your vest to suit your need.
I remember--back in the day--attending a training program at the Maryland State Police Academy, and one of the things that was demonstrated was a dynamic entry by the STATE Team (MSP's SWAT unit). One of the operators had a secondary pistol mounted on his entry vest. It wasn't cross-draw, as I would have expected, but was instead mounted just above and behind his primary handgun. When I asked him about it, he explained that he trained so much to draw his handgun from a given spot that he didn't want to have to train to reach somewhere else. Made sense to me. But the point is that BlackHawk's STRIKE system overlaps into their CQC line of holsters, allowing you to mount a CQC SERPA holster on your vest if the need exists. By using the STRIKE CQC platform, you can mount a SERPA holster at various angles and anywhere on the vest that the platform can be mounted. It's four rows of webbing wide and two tall. It has four attachment points and offers a secure platform for your SERPA holster. Because the webbing slots are 1 inch wide, you can adjust the positioning of your holster to within 1 inch of your comfortable draw.
Now, two things I always tell anyone who asks that they need to make sure are on their vest: hydration and identification. A hydration system pouch--several different colors and sizes in fact--is available from BlackHawk. As long as they are, it actually takes two sets of Speed Clips to properly mount one. I recommend centering the hydration pouch on the back of your vest UNLESS you have a need to mount a radio pouch or something else on either side. And, since the hydration pouch essentially runs the length of your back, I recommend putting the identification patch panel high and centered on the hydration pouch.
Almost everyone needs to carry a radio, and BlackHawk certainly has a carrier to fit your size radio. After that everything is about equipment and supplies.