I've been to Ru San's a handful of times over the years. I prefer a couple of other sushi joints in town mainly due to the atmosphere.
Make no mistake, Ru San's has delicious sushi and a huge menu to choose from. I have no issues whatsoever with the food. Also, the staff has always been very pleasant and attentive. It really is a great place for sushi and I will continue to come here from time to time.
I gave 4 stars just because I don't care as much for the atmosphere. It has a "diner" feel to it and it's rather cramped. It is also a little on the loud side which I don't totally disagree with but when I want a quiet dinner with my wife I'll usually seek sushi elsewhere.
This is a terrific establishment, though, and I highly recommend going!