My answer to that would be that the live bait fishermen you're fishing with probably are not using optimal techniques, i.e. are not getting the most out of their presentations. Live bait fished improperly is no better than any number of lures, not just Gulp. If I had a dollar for every time I've ever seen other fishermen on a public lake fishing with a large float and several split shot and a #1 gold hook on ten-pound-test, with their red wiggler threaded onto the hook so it no longer looks like a worm, catching nothing, and then wore them out myself with superior presentation of the same bait, I'd have several dollars. Just line size alone can make the difference: if the angler using Gulp is using light line, four-pound-test for example, and the bait angler is using ten-pound, just the difference in visibility of the two lines to the fish will make the difference - but it would also make the difference if both anglers were using Gulp, or both were using live bait. If all other factors (line test, location, etc.) are equal, and the bait angler is simply using a hook that's too large as most of the non-expert bait anglers I've ever seen tend to do, that big hook will drastically cut down on the number of mid-sized (under 8") bluegill that the bait angler is able to hook because the hook's size makes it more difficult for the fish to get into its mouth, and the bigger hook will spook most larger fish, thus a drastic reduction in fish caught. Same thing with a too-big float, or too much weight - just one detail of the presentation being wrong can wipe out the angler's chances on any day other than those rare days when the fish are jumping in the boat, and more often than not, in my experience, the average bait angler makes not one but all of these mistakes at the same time, as a matter of habit.
There's a guy on **************** who is a match fisherman, i.e. fishes tournaments all around the world; he has won some big tournaments that had anglers from several other countries as well as this one; and he recently made the same observation I and the other posters above me made, i.e. that Gulp is not bad, but does not come anywhere close to (properly-fished) live bait - he even noted that he did his own side-by-side comparison, and live bait outfished Gulp by more than two to one. And he is a guy who spends most of his time refining his presentation methods - he even designs his own line of floats.
I would gladly take the money of anyone who wanted to wager he could catch as many bluegill (same water, same day) on Gulp as I could on live bait.