Marjorie Liu's X-23 solo series. (Not the one-shot she did earlier.)
Marjorie Liu tried her best to incorporate every single X-23 related story up to that point into this comic but it's all a bit too much and legitimises things nobody should really want to see legitimised like the Captain Universe story.
X-23 being someone who searches for a "soul" because she's a clone is also a wholly uninteresting and ill-fitting story angle.
There is also another problem with this book:
It put the thought into a lot of people's minds that X-23 is a deeply sad and miserable character, something which -despite the incredible hardships she has endured- is not true at all.
Writing her like this hurt the character a lot in subsequent books and in the eyes of readers who started reading her post Second Coming.
Then there is NYX
This book by Joe Quesada is not really about X-23 but it is the first actual comic to feature the character. (She was created by Craig Kyle and Chris Yost for the X-Men Evolution cartoon.)
It's a quite disturbing rendition of the character because she is introduced as a child prostitute.
Normally I would advise to ignore this version of her but Kyle and Yost have actually referenced it in their own work, granting it some legitimacy at least.
Everything else, from Chris Claremont's version completely devoid of character all the way to Brian Michael Bendis' horrible rendition which has nothing to do with X-23 should be avoided at all costs.