I used to work down in Luling/Killona, Louisiana, and my grandfather was from Baton Rouge. I love Cajun food, but I've learned not to touch Cajun or creole outside of Louisiana (or southern Mississippi), with one exception. A couple from Louisiana opened up a hole-in-the-wall Cajun joint here in South Knoxville back in the early 90s called Bayou Bay. The seafood dishes aren't as good as what you can get in southern Louisiana, but the traditional stuff (gumbo, jambalaya, etouffe, creole) is as good as you'll find anywhere in LA.
For those in the Cincy area, Knotty Pine on the Bayou, which is just south of NKU, is pretty good.