Liked it? Really liked it? I loved the central story mechanics - born again, die again, born again, die again. And each time, I'd let myself flood with worry about who's going to die, who'll stay alive, and what new glimpse into their lives you get. But the diversion (as I see it) of that long chapter on the war took me out of the seesaw and the push and pull of the "life after life". In another book, I might have loved this section. Here, I was just impatient for it to get over.
But I'll go with a four, cuz at the end of the day, I fairly devoured the book and was thinking about Ursula even when I wasn't reading the book.