Short history about Russian Webbing Systems
Classic Belt systems
Here you can find one of the most popular Russian type vests - belt systems. They were created for Forest and field battlefields, when you lay on the stomach and doesn't have access to the chest pouches. So, in this case you need to use belt systems. All pouches placed at the edge of the belt, so, you can totally snuggle up to the ground to avoid enemy fire and you have easy access to the pouches to recharge.
Molle Belt Systems
Classic Belt Systems have sewn pouches, so, it's doesn't provide ability to place any other pouches. MOLLE interface provide ability to place ANY pouches on your belt system. But in the same time, they are little bit more expansive.