Too many variables, but in an area with high populations of fish (any kind) 50/50 is possible.
You need to think of the other advantages as well though. Easy transportation, ability to change colour and size easily, the fact that some species dont like softbaits, eg sharks, rays and dogfish.
I often fish softbaits cast and retrieve while soaking baits and score a bonus kahawai and occassionaly a kingfish that may never have seen the bait.
Give it a fair try and see how you go. I doubt that Gulp crabs will outfish real crabs side by side for moki but when you dont have crab baits they could save the day. They did for me at Matakona one day when I had no bait. The moki loved them.
A fair try means fishing them when there are fish around not just when there are no bites on bait.