I started all over again, this time on Medium difficulty. It does add a lot of much needed challenge to the game compared to Easy. I'm still not going to turn off the vita-chambers, though.
I made it through the first couple of levels. I just got to the part where the submarine explodes, and I'm rapidly running low on things like first aid kits and eve hypos. I'm trying to get the good ending by rescuing all of the little sisters, since you're rewarded with a bunch of Adam anyway with the care package, so I'm not sure what the big deal is.
The game feels very similar to Fallout 3, but a bit less open. I do like the fact that BioShock rewards you for killing your enemies in creative ways, since you save on ammo and health, whereas Fallout 3 punishes you by not giving you experience for enemies that your hacked turrets and satellites kill. Saving ammo and health isn't as important in that game, since it is very easy to come by.