Adorkable: Clumsy, a Nice Guy prone to screwing up but being extremely enthusiastic about helping others.
Broken Base: The movie as a whole. Official sources conflict on whether the film was any good or not, and it didn't help that it came right before the critically-panned Emoji Movie. Depending on who you ask, either it's an underrated film that is very faithful to both the original Smurfs comics and the TV series or a complete trainwreck. However, it's pretty popular among the Smurf fandom, though mixed among critics and non-Smurf fans.
Captain Obvious Reveal: Even before the studio and third trailer revealed the lost village is full of female Smurfs, most people saw it coming.
It's the Same, Now It Sucks!: Some viewers were somewhat smurfed-off that Gargamel's motivation for catching the Smurfs is to extract their essence and improve his magic (a plot point that was borrowed from the two live-action films).
Like You Would Really Do It: Smurfette is reduced to the clay she was made from after her defeat of Gargamel, which predictably doesn't stick (though the scene may still be a Tear Jerker while it lasts).
Older Than They Think: At least one trailer and TV spot have declared this the first fully-animated Smurfs film, ignoring The Smurfs and the Magic Flute and the more obscure Les Aventures des Schtroumpfs from 1965 (which as compilation of shorts from the 1961 series).
Squick: The part where Gargamel kisses Monty. He grabs Monty by his beak and proceeds to practically smooch him, what with him making odd movements and suggestive eyes while at it. Azrael is understandably disgusted after.
Some people are irked by the implications of all the female Smurfs being far more competent than the male ones, though it's justified as the result of living in a more dangerous forest.
Visual Effects of Awesome: The CGI is very fluid and colourful. The forbidden forest in particular is amazing.
Win Back the Crowd: Many were happy to see a more faithful movie adaptation of the Smurfs after the poorly received live-action films.