I tried googling but can't get clear answer as I think they changed it from the info I have found.
How is survival mode? What does it all add to the game?
Seeing what people say here while I cross examine all this info.
Survival mode is awesome. I really don't want to play the game without it and I will say I've noticed it also has the effect that I am finding I am more strict about my personal roleplaying. Don't know why but it encourages me more to be stricter to rping my character even when it would be easier to fudge on the rp. I would like to be able to toggle off the save at beds not because I dislike it (I want to save often but I find it does add to my game). But because I want my first character (the one I care more about finishing the story) to not be as stressful as the save mechanic makes it but I don't want to play now without the other features of survival. I'd actually keep the save at beds for my survival character as it really does add something (and honestly beds are not that hard to find. Usually I don't save more often because of 1. rp reasons - if a bed is really out of the way it feels too out of character to go back to it and 2. I don't want to get a disease. Antibiotics are too hard to find to risk getting too many).
But even the save at beds mechanic I'm finding overall adds to the experience for my survival character. I've found ways to get around the rp mechanic by either starting to sleep then cancelling (you don't sleep then but you still get an autosave though also a potential disease too). Or some one pointed out you can also rp it as your character stopping to bandage themselves and lick their wounds for a bit which I may do some too.
The food and eating and sleeping mechanic is balanced much better than hardcore mode in vegas, it actually matters and with the limited weight you can carry actually creates pressure on you. As well as adding in radiation has more effect in 4 and radaway will make your immune system weak so more likely to get diseases (and antibiotics in my game are rare as fuck, I'm guessing they are linked to your luck as my luck is 1). So you really have to be careful how many radaways you use or rads you get. It makes you more careful about that. It also makes settlement building more interesting cause it gives you incentive to put in your settlements stuff like the arch to get rid of radiation and a doctor that can heal you. I've found that my biggest goal with my survival character is building up my settlements as bases and going out and finding materials I need (also for better guns). It actually makes what I found promising about what Todd said about settlements be more true. It really makes settlement building much more interesting as it really gives you a good goal for it (they were mostly ignorable before survival mode if you didn't want to build them but they'll give you huge advantages if you put time into them in survival mode). If you like crafting and mechanics that encourage you to craft and also to go scrounge for stuff to craft with, survival mode really is awesome for that (it does make it more a survival type game. Too bad the dialogue system sucks, that would make it the perfect game, I might even rate it above New Vegas if they had a good dialogue system/rpg mechanic. I hear Far Harbor is good for that though).
I loved the idea of hardcore mode in vegas, but it got pretty easily ignorable except for thirst. Sleep was never an issue (I already rp sleeping every night and even when I couldn't find a bed right away I never got close to being tired enough to affect my game).
And the hunger/thirst/sleep mechanic is balanced enough for rp that you can reasonably see your character starting to need those things when they do in game (and I love that getting tired is also linked to how active you are. Sprint a lot and you'll get tired faster).
Honestly, I am one of the Obsidian > Bethesda people and New Vegas >> 4 and 3 but here is on area I think Bethesda outshined Obsidian. Obsidian had the right idea, Bethesda actually implemented it well. I will say I was disappointed in how they messed up the RPG part of Fallout (most of that tied to their horrible dialogue system as well as lack of skill checks which kinda ties in the dialogue system too). But survival mode seems to be making up for that. I'm not near as annoyed at the lack of rpg but I find as I said it has encouraged me to be stricter on my rp so in a way it has enhanced the roleplay aspect. It's just a shame the game didn't launch with survival mode. It really enhances the game and I don't find the game feels lacking anymore (before survival mode I played 150-200 hours before I got burned out. That is the shortest amount of time it took for me to get burned out on a Bethesda game
).
And btw, like save at beds, you would lose some of the challenge if you could fast travel anywhere. For example in New Vegas, a lot of people found hardcore mode to be negated entirely cause they could just fast travel to that one lake that had clean water and drink there everytime they needed to drink. Here you could just fast travel to your settlement and drink from the water pump. I didn't have the issue cause I don't fast travel anyways by principle in any Bethesda game (I honestly hate it cause for me it breaks immersion a lot but I remember people complaining about that. Part of the fun of the game to me is travelling and trying to survive the travel part).