Splitsville and Kona, and Cali Grill tie for americanized rolls for me.
Kimonos was good but not great to me, for both special rolls and Nigiri not sure why.
Nigiri sushi is best at Morimoto, WPGC (closing,7/31), and Benihana in the Disney Springs Hilton. Rolls at Morimoto were perfectly executed but fairly basic.
Best overall Sushi was at Benihana, at the Disney Springs Hilton that we happened upon by accident having to fly in a day early due to weather, tons of harder to find Nigiri options, fantastic special rolls, and great cocktails.