I was... rather disappointed when I got my Ebisu. It actually felt slightly inferior to the Lu (at least back at the time when I got it; I don't know if it's still the case now) because it offered slightly less time to reel in your catch than the Lu did. (Yes, I am sure there was a difference; I did a LOT of fishing with that Lu)
Course, this is from the perspective of someone who leveled their own WW just to fix the Lu to do the quest. For people who do this, it pretty much defeats the purpose of going for Ebisu if you intend to keep your WW skill. For those that don't level it or don't plan to keep the WW skill, yeah, I could see it being actually useful. Other than that though, there is nothing I can catch with Ebisu that I couldn't do at a similar rate with the Lu. Ebisu doesn't even seem to successfully land Lu-breaker fish more often than the Lu does, the only difference is that any rod breaks I would have had with the Lu are replaced with line breaks on the Ebisu.
I felt rather shortchanged by my efforts overall, but oh well. Least I can say that I finished it.