I have switched from vest, to waist, to chest pack, and to just a lanyard many times. Big problem for me is the waist back doesn't fit right for me. My upper body is bigger than my waist. Then the waist pack falls down and I walk like a duck. The vest is hot in the summer and in the way in the winter with a heavy jacket on. A chest pack is in my way, because of my fat gut and I can't see my feet while wading. A lanyard is great as long as you have a pocket to put your fly box and tippet in.
In a nut shell, I still switch back and forth depending on where I am fishing and how far I am away from the truck. When I take my yearly trip to the Smoky's, I either use a lanyard since alot of streams are rod side. When we hike into the back country for the day I use my Fishpond Shooting Star for my lunch, jacket, and etc. Once we arrive to the stream I then remove the backpack and just use the chest pack (which is a Windwalker chest pack) as a sling bag.
I am far from rich, but I believe in Fishpond and there quality.
BTW, I go back to a vest when I want to be traditional.