The actual VC died in 1986, so most VCA books aren't written by her, and in my opinion, it shows. Seeds of Yesterday is the last of the Dollanganger books written completely by her though Garden of Shadows was started by her but finished by someone else.
Likewise, the first two books of the Casteel series (Heaven and Dark Angel) were written by her; The third book, Fallen Hearts, was started by her and finished by someone else.
There are also two stand-alones written by her: My Sweet Audrina and Gods of the Green Mountain (a much earlier work of sci-fi which I've not read).
Every other VCA book was written by someone else.
I would recommend reading all of her actual books as well as the two she started, but skipping all the rest. The only exception would be Gods of Green Mountain, but only because I've not read it.
Likewise, the first two books of the Casteel series (Heaven and Dark Angel) were written by her; The third book, Fallen Hearts, was started by her and finished by someone else.
There are also two stand-alones written by her: My Sweet Audrina and Gods of the Green Mountain (a much earlier work of sci-fi which I've not read).
Every other VCA book was written by someone else.
I would recommend reading all of her actual books as well as the two she started, but skipping all the rest. The only exception would be Gods of Green Mountain, but only because I've not read it.