The superficial comparison here is to House of Knives:

Both are 3/1
Both can do 1 net damage per run

I think we can do a quick pros/cons here to e-friggin- lucidate the difference.

Pros:

Ancestral Imager never runs out of charges- House of Knives only gets 3 (though they could be topped up with Genetic Resequencing

Its a nice big middle finger up at Au Revoir decks

It could help Jinteki: Replicating Perfection if the runner had the intention of just bouncing say a Shock!ed or Shi.Kyūed up archives to run a remote- they now suffer pain for doing so every time.

Cons:

If the runner doesn't jack out this cannot fire. Of course runs fail, but 'generally' the runner doesn't run with the intention of jacking out. which means this wont trigger. HOK fires when you want and there is nothing the runner can do about this. So HOK's damage is more easily applied and more effectively applied.

Isn't a definite kill after Komainu unless you are PE or put a Fetal at the end of the server. That's one more combo piece required for the flatline.

Cant contribute to the damage done by traps. HOK can fire before a trap access adding +1 to that Project Junebug or Snare! Ancestral Imager gets no opportunity to fire if a trap is accessed.

Conclusion:

Ancestral Imager isn't about flat-lining. -because unlike HOK you don't get to apply the net damage at the opportune moment.

Instead this is about net damage tax. The question is. Will they jack out 4 or more times after you scored this? If you think yes, consider slotting it, if no stick with House of Knives as its objectively better when only required to fire 3 times in a game.

It seems as though its best synergy is with end the run ice because end the run = jack out

Both HOK and this stack so i didn't really review that, but remember 3 damage is better than 1 :)