Anytime I'm in that downtown area, this is usually my place to go to. I found this place after my good bud from Osaka told me that the flavour of the food here reminded him most of what he would eat back home.
I have many a shirt with the battle scars of ramen broth thanks to the slurping down the bowls of ramen, and I wear it with great honour! The food is also very consistent between locations so fear not! Seating is also very comfortable and at a good level. I cannot tell you how many times I've gone to a restaurant and feel like a 5-year old sitting in a booth...
My personal fave? The Miso Ramen.