I actually used to work there full time. It's legit, I packed out thousands of fish. They've been doing it for a LONG time (over 20 years) and I believe they run the largest independent wholesale operation on the entire west coast for freshwater fish.
One thing I will say is that with any operation that large, with literally thousands of fish coming in ever couple weeks, they occasionally might have health issues. However, something unique about them since they have both a retail AND wholesale operation is that all the new fish coming in get a quarantine and treatment period before being sold... They are not in need of tank space and don't move fish if they don't feel like they're ready. However, it is always best to inspect a fish in person, so I'd be happy to check stuff out for you to make sure.