I would say that Takechan is decent but average, not spectacular. High 50s on Supleks though. There were very few people in the place when I stopped in last Sunday after walking around in Yoyogi a bit. The Yoyogi branch (there are only two branches, so I hesitate to call it a chain) is fairly large and has a lot of room to move around in. Stange ramen-themed manga on the shelf. Quite a strong fish flavor from the soup. I think the trick here is that you have to get the hand-made noodles (choose the button with the "平打ち麺" on it. Regardless of whether you do that or not, the pork is still the star of the bowl. You can also apparently order some of Takechan's ramen online here, along with a slab of some of the special pork that they serve. When you bring up the home page wait for a few secs and it will change into a photo gallery that will let you see pictures of the person who is presumably Takechan himself.
Shop home page
Ramen Road blog
Diddlefinger Map (English labels)