I wear a vest at work (5.11 type), mostly to conceal items (I am a plain-clothes LEO). I find that too much weight in the vest is uncomfortable. I also work where it is cool. If I travel to warmer parts of the Bay Area, the vest gets uncomfortably warm. On the plus side, I find that all of the pockets are great for organizing all of the light-weight things that I carry (business cards, LED light, nitrile gloves, hand wipes, notepad, pen, etc.). The heavier items are on my belt, in front pockets, or in a shoulder holster.

I have worn a pilots survival vest for a few days. I found it very comfortable, and capable of carrying more weight. But due to its design and look, it is probably not practical for EDC (unless you are a military pilot).