We’ve tried like 5 different brands of frozen unagi from various stores and brands. Some are great, others were terrible. I’ll leave my summary of good and bad brands here as I find them, kind of like for my tofu!
OceanKist – Very Good

Not overly saucy, but well flavorful and delicious.
It took quite a bit longer than the instructions listed to defrost. Instructions said 6-8 minutes but it took us about 15 minutes. We had our freezer set to the coldest it can go. We cooked until ~130F internal and then broiled for 1 minute and it was delicious. Weirdly the instructions said to cover it but I found it didn’t cook at all when covered, so I just uncovered it and it was great!
Skin was surprisingly crispy. I cooked it in a glass Pyrex which I think helps. The “head” part of the eel had thick tough chewy skin but it’s a small portion of the body and I really like the chew.
Very easy cleanup with the glass, probably would have been fine on a metal tray. I think the low amount of sauce is really nice here.

