I found Seas of Blood a terrific book. But then it was only the second FF I played, so there's nostalgia there, and I was also a fan of stories of Odysseus, Jason and Sinbad, which the book largely scavenged for ideas. But it's extremely tough to win, and with all the extra rules I can understand some people being alienated by it. But it was still great fun, with lots to explore. Appointment with FEAR was complicated, but still fun.
My main issue with Seas of Blood is it should have felt like a rip-roaring adventure with plunder waiting to be uncovered all over, but most encounters seem to kill off half your crew, slap a hefty time penalty on you and reward you with about 2 gold pieces.