Mackerel(Saba) is a very fishy fish.
It has a very strong aroma when you sniff it and iit has a strong smell to begin with. For me it is just right. I think some Japanese restaurant would marinate this fish with some vinear before it is served (if the fish is not freshest I think, as to get rid of some of the unpleasant stale feeling of the mackerel).
Due to its pungent flavor, it sells pretty well in the US and it is seen in a lot of the restaurants(good or bad). It made a good addition to a chirashi bowl (sashimi bowl) however I don’t see a lot of mackerel in rolls, because it will steal all the attention and because of its distinct flavor, it doesn’t blend in well with the other sushi fishes. I have never tried it with sake, but I might taste good. (Bear in mind that sake and sushi is not a natural pairing because sake is too strong in flavor; green tea and sushi is probably better)
Try grilled mackerel, it taste very good because of it’s strong fish taste and its texture. I like to eat the fish skin too.
freashness are not the reason saba is marinate in vinegar before it is served. The main reason is to kill the Anisakis (parasites) that reside on the fish. Also the shelf life of freash Mackerel are extreme short, the marination in vinegar also help to incease it’s shelflife.
for more detail, look under the parasites(寄生虫) and freshness control (鮮度維持) section of
サバ