I used to like vests, the many pockets seemed handy and very functional. I sometimes wore jackets that had loads of pockets. They worked out well enough. The biggest problems were that doffing the load, unloading, and finding things was a pain. I once spent a good amount of time trying to find a small device that I was sure I had in one of my pockets. I didn't find it. A few weeks later, while digging for something else ... there it was.

IMHO a good day-pack, musette, or other shoulder bag is better than a vest.