The Famima post below gave me the idea -- let's compile a list of the best and worst boxed sushi. That is, not a to-go order from a real sushi restaurant, only from a market, deli, etc.
My list so far:
Fish King -- great spicy tuna roll, huge, only $6
Bristol Farms -- good selection, half rolls and sashimi available
Trader Joe's - inedible, gluey