I will often do Shiki-Sai multiple times during my visits - it's a quiet, cool oasis in the middle of chaos! I have 2 res for an upcoming 5-night trip .
I have had the Tokyo negi roll about a million times - love it beyond reason, highly recommend, I could eat one every single day and am now hungry thinking about it. I've also enoyed several other nigiri items, hamachi is one of my faves. Other likes have been vegetable tempura and wagyu gyoza. I was a bit meh on the kara-age chicken (it was fine, but it seemed weirdly tough given that it was thighs) and the sakamushi clams - they were fine, just not my favorite.
I haven't had the ishiyaki-sukiyaki rice since I am always there solo, always get a Toyko negi roll, and can only eat so much - but it is supposed to be spectacular.