Okay, I haven't really trashed any restaurants yet, so here it goes. And this comes with a caveat - other people seem to like these places, so this is my personal view and probably does not represent the consensus.
First of all, I do not like Ichiban's Japanese food. It may be politically incorrect to say so, but Chinese do not, generally, do Japanese food right. Key flaws with Ichiban:
1. For sushi and sashimi, they cut the fish in advance. I've never seen this done anywhere. By cutting it early they decrease the freshness of it. This is not absolutely awful for sushi rolls, as the quality of the fish is pretty well hidden in the other ingredients. It is particularly bad for sashimi, however.
2. The wrong sauces. I ordered shumai (steamed shrimp dumplings), and the sauce was totally wrong. It was like a sweet duck sauce. Shumai should be served with a spot of yellow mustard on the side and it is dipped in a soy-based sauce.
I have the same general complaints about Sushi House on New Scotland Ave. They didn't precut the fish, but the sushi was not that great. The sauces were wrong on the Japanese food.
These places are fine for Chinese food, and if you're not experienced with Japanese food (I lived in Japan for a year) you might not notice these issues. Certainly both places are popular. I have been to Ichiban a few times because people I was meeting wanted to go there.
They do tend to be cheaper than the real Japanese places, but you get what you pay for. The better Japanese places in the area are Miyako, Yoshi Sushi, Saso's, Mari's, and Mino's in Saratoga. I haven't been to the latter 3 in a while - Miyako and Yoshi are just a lot closer to where I work and live. I used to like San & Bada, but haven't been in a while so I can't say. Tokyo Sushi does a half-decent job, but Yoshi's is better and is just down the road.
Of course, all pale in comparison to Megu, but that's not fair since Megu is in NYC and costs about 5 to 10 times as much as the most expensive Japanese food here.