I played both the Alpha and the Beta and had a blast. Especially playing in a group of 5 all on one voice comm.
But it became obvious very quickly, that although this game is beautiful, has its own ideas and plays surprisingly well, that the content delivered will, unless the evacuation mode adds a lot of additional content, not be that much.
As far as I know you'll have 3 playable/unlockable characters per class with new classes and monster being introduced as DLC.
If you preorder, you get the 4th monster for free. Otherwise it costs 15$. Reading that made me gulp. 15$ for a playable character? Unless they add new maps and other things to it, this would definitely be a no go for me.
Buying the game on steam with all announced dlcs will now cost me 79,99?. Again, this is a no go for me.
And just playing the base game? 3 Monsters + 3 characters per class with no further customization options in the terms of long term progression (I'm thinking of gameplay), would make this game pretty short lived. This is not because the game doesn't offer much, but the gameplay variety was even exhausted in the beta:
1. Monster: Run, Eat, Run, Evolbe, Eat, Run, Eat, Run, Evolve, Eat. Smash hunters. (although this can be shortened if the hunters are a random group)
2. Hunter: Follow, Follow, Follow, Follow, Follow. Fight.
That's basically my whole experience over the course of 20 hours in gameplay.
And again, I have to say I enjoyed it a lot and I've been playing games like Counter-Strike for years, I can't see this being as captive on long term as there is by far less skill involved in playing Evolve.