If you're claustrophobic go for the one with the lights in it, otherwise go for the one that looks like a bunker hatch.
Rooms 2 & 3 (the Summer Sky tanks) have enough headroom inside that you can stand up, and the doors are larger so it's a bit easier to get in and out if you might have trouble with that. They also have lights inside (that you can turn on/off whenever you want) so they're a bit more welcoming if you feel any anxiety about the deal. Rooms 1 & 4 (the Escape Pod tanks) are more basic. There's still enough headroom inside that you can sit upright, but not enough to stand. Having less air volume means that it's easier to keep the air warm, and it's easier to make them quiet. Some people like the cozier feeling.
Without the lights, they are all pretty much the same once they are closed. I am not sure it matters.
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