For future use, here’s a couple I can think of in San Mateo:
Viognier. A little stuffy for my taste but quiet and decent food.
San Mateo Prime. Business steakhouse, exactly.
Izzy’s Steaks. Everyone actually says good things about this ( san carlos near SQL ), but I haven’t been.
Vault 164. I think I’ve been there for a business meal. American.
Block 34. New place. Very decent space between tables, good wine list, but a little basic in overall settings. Might be perfect for you.
There’s also a new Paul Martin’s Grill in the hillsdale shopping center. I wouldn’t bring a business person to a shopping center but YMMV.
Central Park Bistro - I think it’s a nice midrange place. I don’t remember how loud it is, exactly.
On the “ethnic” side ( HATE THAT WORD ) I might suggest Champagne Seafood. I am pretty sure they semi-private rooms ( which are really glorified booths ). It’s not seafood only. You’d need someone comfortable with navigating a dim sum menu.
I also might consider The Attic because the atmosphere is a little interesting, the food is a little interesting, but not too interesting.
Most of the other “ethnic” places I would consider too loud for a business dinner, or not fancy enough, or too long a wait, or too hard to get reservations.
[ Delfina was a good suggestion. ]
Where did you end up ? How was it ?