Being a sushi snob, I had always considered Umi to be the city's gold standard. While it still is, Chaya is very solid as well. My sashimi was as fresh as possible, which is the most critical requirement (in the East End, one must carefully avoid some other sushi stops). My son ordered the basic sushi platter, so we didn't give Chaya the chance to show off it's creativity, but his sushi was fresh and well prepared. The dining area is very comfortable as well.
PS - it is BYOB. We stopped at East End Brewing first for a growler of beer, and the crisp waitstaff at Chaya had beer glasses on our table within seconds after we were seated!