The Eternals lacks the humour and cohesion of previous Marvel team-ups (Guardians, The Avengers).
Firstly, they are not as well known as the afoementioned characters. The premise of the film is interesting. But thats about it. The action sequences are OK but the CGI is not as good as other films of this ilk. The 'enemies' (the Deviants) don't bring much to the table and its never really explained why evolution is such a bad thing. The Eternals have also clearly evolved from how they were created and that seems to be OK.
The pacing of the film is slow and the way the Eternals appear to be able to traverse the world in moments when only one of them can fly makes no sense. Which is only one thing that makes no sense about the film. The fact that one Eternal goes from devout follower to suicide risk in the blink of an eye is another.
It seems that in order to include such a diverse bunch of 'heroes' the plot was a secondary concern.
Watch it if you must. But personally I wish I'd saved the ticket money and spent 2 hours rewatching the Avengers.