I've been in the valley for almost a year and so far Sakana is the best sushi restaurant I've found (and I've been looking).
First, the bad: on Friday night I met some friends at 7:30 -- we were a party of 4 and were told it would be a 30 minute wait. The wait ended up being over an hour, due to a couple of large parties just camping out after the bill had been paid. Keep in mind, this is a small restaurant. It would have been appreciated if the staff could have dropped subtle hints to these patrons that there was a slew of people waiting for their tables.
Otherwise, the sushi is very tasty. The soft-shell crab roll is my personal favorite, and at around $9, an indicator that this place is easy on the wallet. Portions are large. Service has been consistently fast and friendly. The decor is simple and nothing ornate, making it feel like a nice family restaurant. People were dressed in anything from gym attire to business casual.
Sakana is on the top of my mind when I think of going out for sushi in Phoenix.