I float tube in Eastern Wash a couple times each year using flies with barbless hooks. I noticed that the only fish lost were break-offs and releasing them was a breeze. Some of those 'bows are HUGE!
Now that Gami makes barbless steelhead hooks I thought I'd give them a try. I have not noticed any significant fish loss while steelheading, but a good comparison might be one of my trips to the Satsop. Took a buddy down for salmon and hit it just right, fish everywhere! The 2 of us must have landed 40-45 salmon, mostly chums, 1 beautiful king hen (25 lbs. released), and brought home 4 dandy silvers. The only difference I noticed was that I was able to release the fish immediately and my friend always had to use the pliers. I strongly feel the only time your going to lose a fish with barbless hooks while drift fishing, is if you slack line. I have no experience with barbless hooks on plugs or hardware so that may be a different story.
As far as cutting your line with a gut hooked fish, is there any other way? Even using barbless hooks, I hate to put any pressure on their gills or throat. Just my thoughts………