Never played either Bioshock game for more than 5 minutes. Not out of disdain. More so out of a weak spine.

That price tag on Steam today is very tempting for both. Making me reconsider my stance.

It appears though, from just the general advertising and what I have picked up though that a good portion of at least the 2nd game is an escort mission. So I pose a question. How much, if any portion, of either game is an escort mission? And during those portions are the escortees bullet sponges like Alyx in HL@ (I don't even think she could die), or is it two grazes of a bullet and they're dead?

I wasn't worried about my companion in any part of either bioshock that could be considered an escort mission.

The first one has a segment where you're escorting a Little Sister for maybe 10 minutes and that's all. The second, you don't need to escort them as you can just drop them off in one of those vents immediately after you pick them up, you're just going to get less ADAM and whatnot. If you do choose to collect ADAM with you, then yes, it'll take a pretty decent chunk of your time in the second one.

I've had a Little Sister maybe take 10 seconds of abuse and she was still intact, I'd advise you to stick close to her while booby-trapping the area along with some mini-turrets right next to her. Her collecting ADAM is the only time she is vulnerable. Don't have to worry about moving forward and waiting for her to catch up since she's actually on your back yelling things.

The second Bioshock has scort missions in where a "little sister" gathers materials from dead bodies but she cannot die, it's you who needs to stay alive while she gathers.  
 
The first one is a masterpiece of gaming. 
 
You should get both, the second one is not as good but non the less a great experience.

Sold.

Right near the end of the first game is an actual escort mission, and in Bioshock 2 there are parts where you have to protect a little sister while she harvests ADAM but those moments are entirely optional (if you ever choose to escort a little sister she just rides on your back and isn't someone you need to worry about until you put her down to harvest). Well, the first instance of this isn't optional, by memory, as it's a tutorial, but outside of that you don't have to deal with it at all if you don't want to. I actually found protecting the little sisters a surprisingly large amount of fun, they play out like little combat puzzles where you lay out traps and then let the chaos ensue.

The little sisters aren't that resilient, but I also don't remember ever feeling like they could die too soon.

I preferred the second game. The combat is much better and the first game got boring towards the end.

Minerva's Den, the DLC for Bioshock 2, is the absolute best part of that game. Get it.

@Ygg said:

I preferred the second game. The combat is much better and the first game got boring towards the end.

This topic could be about to veer wildly off topic, but I think I prefer the second game as well (at the very least I feel it is on par with its predecessor and largely underrated). Its story isn't some grand commentary on videogame design, but I think it's a more heartfelt story that stays strong all of the way through (whereas the original lost me in the third act) and Sophia Lamb made for one of the few villains I have legitimately despised. The gameplay is better for the most part, it's just that none of the levels stand out like Fort Frolic and the game tries a little too hard to hit the same notes as Bioshock to its detriment. The Big Sisters were also a missed opportunity; I would have much preferred the Big Sister were more of a SA-X style enemy. The fact that you know exactly what triggers a Big Sister's arrival and that they're not really any more difficult than a Big Daddy to take down means they're not a terribly threatening enemy - something I would have liked them to be. The game also doesn't end with a big, dumb, bossfight.

Didn't play the second one, but in the first you have only one part of the game that is an escort mission. When you acquire the Big Daddy suit (somewhere near the end i think) you have to follow a little sister around while she gathers ADAM. It maybe takes 5 minutes. 
Anyway you should really give it a go, behind the splicers and the over the top plasmid powers you'll find a very interesting commentary on human nature as you sink deeper and deeper into Rapture and the horrors it holds. Bioshock is the second most atmospheric shooter i played, after Stalker of course.