I'm not sure if you will be satisfied. I'm really not even sure yet if I am. I wouldn't say there was anything bad about the finale, I didn't come away thinking, "six years all for nothing!" But at the same time there are many questions left unanswered. The thing with LOST though, is that they do answer questions, just not the ones you are expecting. You expect a TV show to go a certain way, in theme, plot, characters, etc. After watching so many shows throughout your life you become used to how things will play out, and sometimes a show will shake it up a little and surprise you for that episode, but ultimately the formula is the same. I can honestly say that this is not the case for LOST. It is a different kind of TV show that I don't think we've seen before and I'm not sure we'll see again. It doesn't follow a formula. It is always surprising you, not just with plot twists and turns, but with the whole point of the show. You may think you know where the show is going and what the point of it all is, but you are likely wrong. So I think, that many people were, rightfully so, expecting the show to be one thing, to ask questions and then answer them, or at least give some vague hints. And in many cases it does, but the show turns things upside down and says, well, maybe those questions weren't really important to begin with, maybe there are other things going on that were the true focus of the show.
Anyway, I'm sure that all sounds rather vague, but honestly even if this were a spoiler thread and I could explain everything it would not make any sense to someone who hasn't seen the show, and it wouldn't be any less vague! There are things that I liked about the ending, there are things that I felt they left out, but there was certainly nothing that I hated.
And I think that, most of all, the show was worth it, whether the finale was awesome or not. I really enjoyed watching it, it was so much fun, and I think you would enjoy it too. Just go into it knowing that any burning questions you might have after each episode, might not be as big a deal as you think they are, and remember that at its heart this is a show about a group of people who survived a plane crash on an island.