They're not called Vita Chambers in the System Shock franchise but I can't recall the correct name atm.
Anyway, do you activate them?

I did in the beginning. Then I realized how much of the immersion and suspens suffered from it.
There's almost no challenge left after you have activated a chamber.

I guess that's why Ken and the bunch made it an option to turn them off in a Bioshock patch.

I'm of two minds on this. On one hand, I think it cheapens the suspense needlessly and I don't like it from a game design perspective. On the other hand, I think anything related to quantum mechanics (fiction or digestible non-fiction) is incredibly cool so sign me up for the machine that reconstructs every atom of my body in another part of the universe upon death! At least the design template made sense in the System Shock universe. One of my key gripes with Bioshock is that they reused so much of the design and even story elements even though it makes no sense (Vita chambers, hacking, vending machines being forced into steampunk territory just because).

Anyways, to answer the question, yes, I do activate the Quantum Bio-Reconstruction Machines though I tend to reload a previous save upon death unless the death makes sense from a roleplaying perspective. NO SAVE SCUMMING!

They do cost nanites if you get revived, and if you don't have enough you stay dead, so at least there is a penalty to using them. It's not like Bioshock where there is exactly no cost to using them.

In Secmod, a mod for SS2, the chambers won't heal you to the max either.

If I didn't have them I would still use saves. I would need to have an ironman mode added to change my ways.

A bit more like the original then. That said, they didn't cost money in the original.

I enable the resurrection rooms. If I die, I might accept the respawn or I might just load a save, depending on how I feel about the death. But their existence doesn't change my playstyle at all; I find being killed to be rather disheartening, and tend to play cautiously and keep myself healed whether I've tripped the local quantum bio-reconstructor or not. I guess not everyone thinks like that.

Objectively, I'm not sure they add a whole lot to the game, though. It seems intuitive that the existence of QBRs makes the game easier, but there are no restrictions on save/load, so that's not exactly the case. What they really do is add a bit of a cushion for players who don't save as often as they should - but only after those players have found the local QBR. Experienced players know where to look, but they shouldn't need the help; it's new players, with no memories of the Von Braun's layout (and ambushes), who are the most in need of an emergency alternative to "load the auto-save".

Perhaps their existence leads some new players to stealthily explore the 'safe' areas of a zone until they can flip the QBR, or to contemplate the "your auto-map is filled out" O/S upgrade so that they know where to look; I wouldn't know, it's been far too long since I first played. Other than that... I bet there's some speedrun somewhere that performs a speed-booster-assisted suicide into a wall in order to shave off a couple seconds via quantum bio-reconstruction, and I guess that'd be good for a laugh.

I don't particularly care about using them or not, although I don't like dying, so I still play as if they weren't there and make every life count. If I do die, fine, I'll restart from the chamber.

I have actually managed to complete System Shock 1 without ever dying, but it was mostly an affair of saving and loading all the time, so depending on your point of view, that might actually be worse.

They don't fully heal you in the base game either.

Interesting to note that System Shock actually plagiarised the vita chamber idea from Bungie's Marathon trilogy. they had it first in the form of Pattern buffers which were bio resurrection in the story but in gameplay were a checkpoint system that you saved manually at like in Shadow the Hedgehog. Unlike the Shock sisters, in Marathon, you saved your game at a vita chamber, saved at the next one but you could choose to save at any accessible one available so I could lose 99% health, heal up and run ALL the way back to the last buffer to save or to the next one braving the dangers of Durandal (the male Marathon equivalent of both SHODAN and Cortana), Pfhor aliens and pools of lava or purple jam.

All system shock 1 and 2 did was make them function like the story said they did and claim the idea was theirs when it clearly was not.

then again, i'm not surprised to see everyone believes system shock started pattern buffers considering until Aleph One, Marathon was a Mac only game and Mac computers are absolutely shit.