I give it 6/10 - this shows how that compares to my other films on DVD
http://www.imdb.com/mymovies/list?l=16108977
Antichrist requires concentration for the whole duration of the film but that's not a bad thing. However it is too one-track about grief exhibited in a way that doesn't remotely correspond to what I have personally experienced or seen on film, and whilst that seems ok to start with, it just drags on for far too long; however that emotion seems to be the sole purpose of the film (more or less confirmed if you watch the extras on the DVD).
The mutilation violence did look quite realistic and so did make me wince slightly (probably a 2nd viewing would make it seem quite tame - that has usually happened with other films).
So, overall, a bit too monotonous and unremittingly sombre yet not engagingly deep for what it purports to be; thus I'm unlikely to watch it again soon.