The sushi at Maru, newly opened on Burnet Road, is delicious. It's a place I would highly reocmmend.
The sashimi is amazingly fresh and beautifully prepared. We have tried the fatty tuna (very good), bluefin (a gorgeous red color, wonderful) the yellowtail (good), the yellowtail belly (amazing!), the white tuna (really good), and the uni (a standout). I can't emphasize enough how fresh everything tasted. It is, in my opinion, of equal or better quality and taste than any place in Austin.
Other menu items have been good as well. The miso is quite tasty (but not, as Kate Thornberry said in her review of Maru, the best ever), the dumplings are delicious, and the "J-bomb" -- crab meat, cream cheese, and jalapeno, all covered in tempura batter and fried is lovely.
After visiting twice, I've decided there is one rule to Maru -- either customize or avoid the rolls. The two types we tried (a shrimp tempura roll and a mystery roll that was brought by mistake) were almost drowned in sweet sauce and failed to impress. I probably could ask for less of the sweet stuff, but with sashimi this good, I'm happy to skip the rolls.
Fish shipments come in on Monday and Thursday - so if you want the freshest available, go then. They also will take special orders (for agi, for example) if you ask them a day in advance.
The ambiance is comfortable. It certainly does not feel "fancy" like Mikado or Uchi. The servers seem to be brand new, and there are some hiccups in service that you might expect. The sushi chefs obviously know what they're doing, and everyone is extremely friendly. It's a great place for a casual night out.
Maru is BYOB. I recommend heading up to Asahi (6105 Burnet Road) and purchasing a bottle of sake before you go (the owners are happy to make recommendations)