At $45, Tachi is a good intro for anyone who has never had omakase. The pieces are more common so you're not going to find any uni and whatnot but regardless, the fish was fresh and tasty.
The experience itself can feel somewhat rushed for some people (30 minutes including payment) and there are no chairs since everything is served at the bar.
Don't come here for a sit down (literally) dinner to chat with friends, but it's good for a team lunch or quick bite before an event.
If you're still hungry after, Tachi is conveniently located in Assembly Hall where there is a variety of foods to choose from.