Sushi @ The Lake has always been one of my favorite places in the Cornelius/Huntersville area and one we have visited often.
I would give their quality and overall taste higher marks than any sushi restaurant in the area, including Eez (who charges double but packs their rolls with rice).
The Spider, Volcano, Surf & Turf are all excellent examples of great rolls. Prices are very reasonable and it's a neat atmosphere for sushi.