Dave,

I use the Fishpond Blue River as a sling pack and love it. I push it around to my back and it is not int the way for stripping line or landing a fish.
I keep the waste belt a little lose and it stays close to my body, when I need it I just pull it back to the front. It will not hold as much as a vest but I found I do not need all that can be put in a vest.