I've been on a binge lately on survival games and after doing a search this thread came up and more_badass said I could bump it.
I've put in some time with The Long Dark, The Forest, and Subnautica. I don't have Stranded Deep but I'll get it at some point.
I actually really enjoy all three games but I think each is different enough to stand on it's own. I'll list some things about each game with it's traits.
The Long Dark is incredibly fun exploring, investigating an abandoned hydro electric dam, ruined farm steads. Your constantly on your toes while exploring outdoors because even if you have a rifle or bow to fend off wolves or a bear. A blizzard can just as easily freeze you to death.
My Biggest issue with TLD is if your playing the long game in sandbox mode. While there's plenty to see, if you decide to hunker down a specific spot things get kind of old. There's no structure building in the game and there's few items to actually craft. So after day 50+ you're basically just cooking food, boiling water, or chopping wood. I know that the devs are working on story mode but I would love it if they could give sandbox mode a little love with some new crafted items and possibly some more wildlife. As it stands there's only wolves, bears, deer and rabbits in the game.
The Forest is vastly different, food and water is way easier to come by than the TLD. The game is way more combat oriented since the main antagonist is the cannibals that live on the island. The combat is kind of like a faster paced version of Condemned focusing on melee, although you can craft a bow which is really good against the mutant cannibals. The cannibals are relentless as well, constantly probing and attacking your base and seeing what your up to. Their AI can be unpredictable at times as well.
To combat the cannibals you can build elaborate bases with traps and using walls to protect yourself. Other than the bow though most of the useful weapons you'll use are found in caves, items like a powerful axe which is used for chopping down trees and a powerful melee weapon or you might find a cache of dynamite.
The Forest has come a long ways in development but it still has quite a way to go. It seems like there is some type of end game planned though with a story. The devs do constantly update it and just released a new build today with some new stuff. My thing with the Forest is compared to TLD, is that other than the caves the actual island of The Forest just isn't that interesting to explore.
Subnautica however, is just simply amazing. It's still fairly early as well, the risk vs reward of exploration searching for materials is really well done. Often times pushing you into dangerous areas so you can look for something to upgrade your sub or base.
The aquatic wildlife is so amazing and cool. You'll often times see something and go "wtf is that?" in astonishment and wonder if it will hurt you. The environments are gorgeous, the water looks gorgeous.
The dev is also incredibly transparent showing what they are working on, and what they plan to do next.
https://trello.com/b/yxoJrFgP/subnautica-development
I would recommend each title based a persons preferences.
If you want something that focuses on exploration and don't care for base building. Go The Long Dark.
If you want something that's more combat oriented where you can create sprawling bases and traps, go with The Forest.
Subnautica is just really freaking cool.