i had mixed feelings when i watched the finale, it was really moving and frankly beautiful, but i was so mad because the characters only found happiness after they died, they couldn't get over their problems and mistakes in life. plus the series always had the philosophical debate of science and faith and in it almost every phenomenon that occurred had a scientific explanation, which i found very convincing and suddenly they end the series in a very spiritual way.
Then i thought it was a very unfair finale because the characters never found happiness while they were alive and no one really knows if the afterlife really exists (we'll have to wait til we die to find out), so i couldn't bring myself to think Hey they found peace and joy in the afterlife.
I just really would have liked to see the few that remained alive to have a really good life after all they went through.