The movie had Ninjas in it! How could it not be good?
On a more serious note, I thought the movie was quite good despite having quite high expectations of it from what my friends had told me. It was interesting, engaging and didn't feel nearly as long as it was. Although it did suffer from a little excessive melodrama towards the end, it pulled most of it off quite nicely.
I'm not sure why so many people had problems with Tom Cruise. I've seen better performances but his was certainly not bad at all.
And I hated Underworld, it was a terrible movie whether you watched it before or after The Last Samurai.