I actually just watched all 4 seasons. Really, really enjoying it.
I really love Rumpelstiltskin and Hook.
Some random annoyances though. Why does Emma's "Super Power" of telling when someone is lying seem to only come into effect if it is needed for the story (and it is also completely forgotten in the first couple of season when some pretty big lies were told to her and she did not call anyone out).
Another thing that annoyed me on Season 4 was how all side characters got dropped completely until the fairy tale "Heroes and Villains" episodes at the very very end of the season. I was enjoying a lot of the side things that were going on.
Ok, random prediction for season 5. Rumple clearly has no power now. At some point he is going to have the chance to get the dark one's powers back but will give it up for Belle.