Zaxby's, Raising Caine's, and Guthries actually are all the same group. The execs of Caine's and Guthrie's are part of the original founding trio of Zaxby's. Atleast the Zaxby's and Caine's guy are. The Guthrie's guy may have just been a top exec in Zaxby's from the beginning. They all had disagreement along the way about franchising and other ways of doing business, so they both left Zaxby's at different intervals.
I haven't had Guthrie's. My last town of 16 years, and wife's home, now has one. I might check it out at Thanksgiving and see how they measure up.
Raising Caines is also almost identical as well. Sauce and slaw is same. Chicken is has less and different seasoning. Fries are just plain crinkles and more to my liking.
IMO, Zaxby's has gone downhill. Especially last 2-3 years. And over the years I kinda grew tired of the heavy seasoning on everything. After you've had different things on the menu they began tasting the same. I exempt the salads though. Still like those.