This is absolutely my favorite restaurant in Portland. I would eat there every day if I could afford it. I spent a bit of time in Japan when in college, and this place brings back those memories like no other. It's small, humble, unassuming, but the food is excellent and authentic. The staff is great, and they remind me of Japan as well. Part of me wants Ikenohana to buy new furniture, but another part of me wants them to keep things exactly as they are. I love the salad with the ginger dressing that comes with the meals. The miso soup is also perfect. I often get a Bento box with Sushi/Sashimi, tonkatsu, tempura, and that sweet cucumber salad with shrimp (forget the name)... and a large sake (evenings only, of course.) The chicken katsu is also excellent. Their teriyaki chicken and beef have never disappointed. You can generally roll me out of that place when I'm done... I have no self control there. Also, when you're there you will notice that most of the customers are Asian... which is also a pretty good indicator of authenticity and quality.
Pros: Authentic food and atmosphere... feels like Japan.
Cons: Doesn't look impressive. Not open 24/7 :-)