I've been listening since 2010 and I tell my friends and family to listen to the first chapter to see if they want to listen further, and so far all of them have liked it. There are some lulls in the story where it seems to go slow, but they put that time towards character development and building up to key events in the series.
For those saying they don't like some of the characters... well, what would happen if you randomly selected around 35 people from a crowd? Would some of them annoy you? Most likely. Just imagine those 35 people being stuck together trying to survive, and of course you'd get conflicts- a lot of them. (Of course there are more characters than just that, but that's just an example.) I think it gives the story a sense of realism. Even the "annoying" characters that remain in the later seasons become less so (become easier to relate to, change of attitude, etc), and end up being more key to the story or are killed.
We're Alive was created with a conclusion of the story in mind, and thus it will end with Season 4, which means it has a steady progression of a story line and isn't dragging on just for the sake of continuing (I'm looking at you, The Walking Dead). The characters have some dumb moments (season 1 and 2), but generally this isn't the kind of show where you feel like breaking the 4th wall to slap some sense into the characters, and they get progressively better at their tactics as the story goes on (their enemies constantly adapt and change, as well).
The story is more than just survival, so don't let the title fool you. It's more along the style of a mystery series, but with a setting of warfare. If you like zombie stories but always wanted something more than repetitive battles and fleeing from a predictable, unchanging foe, then this is for you. The only people I would not recommend it to are those who are easily disturbed by gore or horror stories already.