Top-quality fly fishing vests is a massive benefit, whether you're fishing for an hour or all day. But if you fail to invest the correct amount of time getting your fishing vests set up in the most logical way for the method you fish, you'll ultimately be spending more time searching for stuff than casting.
Choose your fishing vests that have wide shoulder straps and neck support this helps spread the weight. I prefer a mesh back as it makes the vest lighter and also provides airflow to keep you cool.
Fly fishing vests are not a fashion statement it should be functional. I suggest you buy at least a size larger than normal also allow extra room so you can fit a good thick fleece under your fishing vest in the colder months.
Pay attention to the quality of zippers on the pockets etc; as they get a lot of ware YKK are the best and last the longest.
Other types of fishing vests packs that are detachable from the pack are also worth thinking about. It's a personal choice.