A lot of people on the internet have been calling it stupid ,and not true to the series, and generally hating it. I liked it. I LOVED it! I cried when Sawyer and Juliet found each other again, and several other times during the show. It summed up the series quite well, even if it didn’t answer every single question (which the writers said it wouldn’t, by the way). the best summation I’ve found was from Tom Richmond.
Six years of my life were taken up by this amazing show, and it will be hard to find any T.V. that’ll fill the hole this is going to leave (although Fringe is doing a good job of holding my attention).

Update: More good thoughts here
And something making the rounds that is (supposedly) from a writer on the show http://www.spoilertv.co.uk Whether it really is one of the writers, or not, it makes good sense.