Barrier Reef is the closest to me, and IMO has the best fish and coral selection. Their customer service is kind of iffy depending on amount of people they have at the time, but still great no matter what.
Ocean by Design has the best customer service hands down, they do have a decent selection of livestock (not a lot when I last visited but granted it was like 4 weeks after their last shipment in so that was expected). But the fact that they QT their fish makes up for it. Their equipment selection is quite limited, but you're mainly there for the livestock anyways, so doesn't really matter to me. But the best part is, the kid (owner's son) is ADORBZ.
Sierra Fish and Pets, I don't really know how to review, their selection is very nice with a lot of dry goods and live stock, but their customer service and employee knowledge is very iffy and depends. I'd suggest you give a visit if you're close, but not worth the drive if you're from far away. Visit barrier reef instead.
So to rank of selection:
1. Barrier reef comes on top hands down
2. Sierra & OBD is even depends on what you're looking for and when you visit
For customer service:
1. OBD definitely comes on top
2. Barrier reef follows 2nd
3. Sierra comes in third
Just me 2 cents