Ok let's review 7 Days to Die,

This is a game which is a mix of Rust and Minecraft. You can build a fort and kill other players but you can also mine quite deep down. Most of the time however you will be scavenging for supplies and fighting various types of zombies on the surface.

The good points of the game are many. First off being that when you make a game a lot of options are configurable. from deathpenalties to night durations and zombie behaviour and lots more. This is definately an upside as you can tweak the game exactly to your wishes.

Second off you will have a lot to do: you will need to build a shelter and secure weapons and gear and foodsupplies. All the time being harassed by zombies. While these are more of an annoyance than a danger it changes a lot when you encounter zombie Rottweiler dogs. or even worse: a herd of zombies which spawn at least once a day.

By being carefull and sneaking a lot you can avoid most of these however. And the gameworld is big enough to keep you entertained and yet small enough to not need verhicles (as the only verhicle ingame are Sedans and those cannot be used by players, don't worry though: zombie's cannot use them either).

But of course while the game has many upsides it also has it's downsides. Especially because it is still not finished.
The most prevalent one of these is multiplayer. You can make a server and have friends join but it is far from stable. I had a friend join a few time sand now he is unable for some vague reason. Also the settings of the game can be changed with each loading and some of the parameters (like passwords) seem to reset between sessions. so if you intend to play this game with a friend or friends I would advise waiting until most of that is fixed. Right now it is just not stable enough for that.

Other downsides are various small bugs and annoyances but mostly those can be worked around. Such as building collapsing quickly because they arenot load bearing, which unfortunately also affects mining veins as partof the veins collapse on itself making you lose the ores that fall. Also grass being in the way of a zombie you are trying to hit is a frequent annoyance. Removing all the grass near your house/schelter is therefore advisable as some zombies crawl.

If you are looking for a good survival singleplayer adventure then I would advise this game. Note that the storyline is not yet ingame so it is a bit sandbox.
For multiplayers I would advise waiting until this game gets a bit more stable. After that I think it will be worth playing.