I feel exactly opposite of this. To all of those who liked it, I can't imagine why. I have trouble understanding how anyone who actually watched all six seasons of LOST and was emotionally invested in the story could say that the ending was perfect. I just don't get it.
I've explained it previously, but I'll say it again. I did not like the ending because it disregarded and invalidated everything that happened in the last 2 seasons. All of the time travel, the bomb going off, Juliet saying "it worked", and the side flashes were all leading us to believe that they were going to change things. (Even Desmond believed everything was going to be ok. So, what, he was seeing into his afterlife while still alive???) All of that fluff was pointless. If they were just going to meetup in the afterlife, this could have been told in a story that didn't have all of the extraneous stuff in it. They could have wrapped it up at the end of season 4. Nothing happened in season 5 or 6 that was pertinent to the conclusion of the series.
I find it interesting how those who liked it call anyone who disagrees with their opinion "haters". LOST was my favorite show, and I have just as much of a right to dislike the ending as you do to like it.