Sushi Samba is my favorite place to eat in Las Vegas. I have been there seven times now, and everything (nearly) is perfect each time.
I would probably recommend staying away from the 'Tasting Menu.' This is when you tell the server what you like and they bring things out for you. Almost always they bring too much food and you spend way more than you intend too.
Absolutely try the mini sea bass tacos, sea bass skewers, and any sushi!
The Saki menu is impressive, extensive, but very expensive. I don't know really know fine Saki, so it is hard to justify $100+ for something I don't appreciate and typically stay away from that too.
Overall, Sushi Samba is one of my favorites in the country.