To put it straight forward, this movie has its fair share of reviews from both ends of the spectrum. Is this a perfect film? No, far from it. Is it an awful film? I don't think that either.
There are reviews calling this the 'worst shark movie ever made' and a 'waste of time'. Though it is definitely flawed, I wouldn't even go near that. When people say that, they must either be referring to the entire film or just the third act, because the sharks really don't even show up until then (this is actually a bit of a compliment).
Yes, the CGI sharks don't look their best, especially at the end. But I'd guess that the VFX team didn't have the required time to perfect them. And (spoilers), the ending with the shark killed by chomping on an anchor, feels like it was just pulled from "The Shallows".
But, there are actually some great (and even amazing) aspects to this film. Though the third act is where it all just kind of falls apart, the story is decent and the build up to the characters getting stranded at sea, and the tension of when their supplies and shelter get smaller in nearly every scene, is done pretty well. And the cinematography, especially in the beginning, looks absolutely gorgeous and professional.