Never went here when it was the home of Akita but 520 met/exceeded our expectations.
The food was excellent. We noticed the little details like the crispyness of the seaweed wrapping the handrolls, the pleasant hint of rice vinegar in the sushi rice, the thin batter coating on tempura.
Service was very good. We ordered everything wirelessly/paperless using a ruggedized tablet placed at our table. We added new items (and seconds) during our meal. We got everything we ordered. Only one nitpick that won't affect my rating: using plus or minus buttons is a little slow when ordering sashimi (i.e., by piece). Food service and cleanup was prompt -- never felt like we were waiting long for food to arrive, or empty dishes piling up.
Price: typical for AYCE; very reasonable for kids (e.g., 4 y.o. was $5 and 7 y.o. was $10).
We will definitely be coming back.