My favorites are;
It's popular to tourists, too but I like their ramen. (Last month I went there and saw many tourist lining up!)
I feel their ramen is healthier comparing to others but more tasty. Their tsukemen is very good, too.
Chorori has a bit more local atmosphere. I have never seen tourists eating here. They have a simple soy sauce taste ramen. Feels very good to my stomach, not too oily. It's also notable that Chorori is open until late.