While I was in Fukuoka, best ramen i guess is Hakata Issou, its not very well known to tourists but it got a recommend from matcha-jp. Went there for dinner and really its a small corner lot shop. Had to wait for a place with my family but it was about 10 mins b4 we got a table. All patrons there were locals except for us, i guess the best ones would be those tucked away places that locals would go for.