I prefer realistic with a good story but I won't shy away from fallout-like settings

If I wanted realistic I'd watch the news; give me fantastical. I want C&C. I want "Hell Comes to Frog Town" and "World Gone Wild".

Sci-fi for me. I like seeing what ideas creators come up with for their worlds.

Realistic works too, but can lead to a more depressing world view like The Road was. I have played games with sad storylines and enjoyed them, but overall I like games with more sci-fi elements when dealing with post apocalyptic settings.

Both, equally. I'm a sucker for anything post-apocalyptic. For me, what the scenery looks like, weighs more than whether or not there are mutants or other fantastical elements in there. It has to look convincing: that the apocalyptic event really happened. That means lots of death (such as dry soil and withered flora) and ruins everywhere- and definitely nothing green.

Realistic can hit pretty hard.
I like when it makes a lasting impact.
It is a real kind of scary.
It brings anxiety out in the thinking man because it could happen in rl given the right circumstances.
I cannot think of anything else off hand besides The Road that hit those notes.

I gotta go with Sci-fi though if I had to choose.
Sci-fi post-apocalyptic just has more to work with.

Yes, actually what I was thinking about with "realistic" PA is those great images you can find all over the net of "abandoned" urban areas, trees and plants overgrowing wrecked old buildings, like the forest/nature itself is taking over these concrete towns.

I find it somewhat more interesting than the typical desert wastelands.

I prefer something with at least a scientific basis that makes it believable, but I can suspend disbelief if its got a high enough "cool" factor to the rest of it.

Realistic. It's already a stretch, to imagine a post-civilisation, post-technological world, no need to add vampire laser mutants from space. I like the idea of junk used to rebuild tools, but when it goes as far as death rays and jetpacks, it loses me a bit.

That's why I always prefer the beginning of the fallout games to their power-armour-plasma-rifle endings. And why I look forward to that mad max game.

I like my PA games to be sci-fi, the whackier the better.

I like both, I think both have a place.

On the Sci-Fi part, a little wacky isn't a bad thing, Fallout does it really well, usually with little things. I enjoy the humor and occasional poke at pop culture, as it's not so overwhelming that it detracts from the story or the game itself (even the Energy Weapons/Aliens doesn't seem to). The Tech is just kinda neat the way they've done it with the era flair that doesn't detract from anything either. So it's very PA, without going over the top in the ET.

Realistic is fine, but that really matters a LOT on balance. If hunger, disease, thirst, and the like really get in the way then it can put a damper on the whole experience. I don't enjoy playing a game where I'm worried more about these things than I am playing the game. If it's all I'm doing, then it's kinda a fail. But if they are there sorta in the background then it's less of a big deal. It just has to be a very careful balance.

That being said, I enjoy the environments of both types of PA games a lot. Story, Gameplay, mechanics regardless of setting matter the most, and I'll enjoy the hell out of either and/or both.

Mix them up. Give me realism for that harsh survivalist hell, but don't go so overboard that I'm infuriated by micromanaging. Give the sci-fi fantastical elements, but don't make me think I'm playing Might & Magic with a radiation meter.

Also, what about medieval/not futuristic post apocalyptic settings? Like an asteroid apocalypse but in imperial pre-industrial China?

Personally, I would take something like Doom: A demon invasion. Whether those demons make us turn our weapons against each other or make a direct assault, that's another matter.

Seeing as how Fallout 1,2 are the best rpgs I have ever played, bar none, I guess I prefer a bit of sci fi in it.
Nonetheless, the Mad Max theme could also work exceedingly well if pulled of correctly, and that is far more realistic than Fallout. I suppose in the end it boils down to creating a gripping atmosphere and I am sure that can be achieved with or without realism

I prefer some science fiction in my post apocalyptic games because if a post apocalyptic game is realistic, it wouldn't be fun. It would be extremely difficult while being boring at the same time. For example, drinking some water to prevent dying from thirst and then later dying from the radiation in that water = no fun. In such a realistic game, 90% of your time will be spent looking for food, water and a safe shelter instead of pimping in New Reno and slaughtering super mutants. :P