I thought it was quite unique and difficult to compare because the
fish has ripened. When caught the herring must have a minimum
fatpercentage of 16/18% to be called 'Hollandse nieuwe' so the fish is
very fat (in July the fish even has a fatpercentage around 25%) and the
ripeningsprocess makes it briny and lightly salty. The quality and
taste of Hollandse nieuwe also differs tremendously.
So because of the particular taste I thought it wouldn't match with the
vinegared rice but I was wrong, I liked it a lot (I made the shari
kansai-style and a tiny bit sweeter).
I only bought two Hollandse nieuwe and I couldn't resist to eat the
first one with some chopped onions, so I had one left to experiment
with. Next time I need more :-)
Personally I like to eat most kinds of sushi without shoyu, but I guess
that if one likes shoyu with regular sushi one also likes it with the
hollandse nieuwe sushi.
I think that as yakumi kizami negi and shoga would be nice, maybe
momiji oroshi too but I have to test this next time