The fad for zombies / zomboids (fast or slow, living or other) has about run its course, which is all to the good. China Mieville pointed out the lethargy in the mode could only run a little while before the grisly edifice spluttered to its knees. Crossed is an attempt to reinvigorate (re-animate?) the genre by making zombies threatening again. The monsters in Crossed are alive, sexually rapacious, immune to pain and generally just vile. And they love what they do!
The monsters of crossed are (almost) shocking. There is no line Ennis won't cross in order to get a grim chuckle or confirm to you the hopelessness of the survivor's plight.
It's good, basically, and I recommend you go read, provided you can take your coffee black and sugary. The plot and all the rest is as you would expect - a band of survivors amble across America, gradually picked off by internecine strife and terrible luck. Ennis is really a very good character author, and the survivors he creates are likable, humored, varied, consistent, growing, failing... and yes, occasionally, being raped to death while their intestines slop out through a laceration in their stomach wall.
To whit - it's not for everyone.