I found it completely emotionally satisfying. The gave each character arc an end.
I didn't care for the "light" at the end, but given the extended metaphor used throughout the series, that would have been difficult to avoid. They tried to keep the show out of the religious bucket, but that is difficult to do. I had the same problem with the end of Connie Willis' novel "Passages". It is difficult to be spiritual but not assign a religion. In reading reviews after the show, a lot of reviewers did not get it. They reverted to thinking that the whole thing was a dream or they were all dead. My quibbles were exactly the ambiguity that would allow people to think that, even though they explicitly stated that was not the case in the show. There were a lot of heated arguments on abc.com on and lostipedia on just that topic. *** SPOILER?**** Part of the problem is that Jack is ultimately the viewpoint character. It "looked" like an ensemble show, but the end only works if you understand that we don't see anything that Jack doesn't know. We don't know what happened on the island after he dies. Hurley and Ben continue their stewardship and later die themselves but we see none of that. So it's initially confusing to see them at the gathering with the others. All in all, better than Battlestar for me. I would love to go back and see every episode now. I wouldn't do that for Battlestar. (I never saw the 1st two years of BG and still feel no need to see them.)