Interview with the Vampire is the vastly superior book of the series. Then again, my favorite is Louis and I consider Lestat the unreliable narrator (which is FACT, given how much of a demonstrable lie his statement that he only kills evildoers is). Louis is the superior, deeper narrator in every way not hampered by constant self-aggrandizement and more introspection.
The retcon of who Lestat (the villain of IwtV) was is the most regrettable decision in her book series. Thankfully, Neil Jordan's film stuck quite strictly to the original characterizations and not the retcon romanticizing abuse.
I always find a vampire story in which the vampire is horrified by what he is to be superior to a vampire who loves what he is. The Tale of the Body Thief is less than other versions of the trope (Doctor Who's Human Nature/The Family of Blood, Angel's I Will Remember You, Smallville's Hidden, etc...) because you never once believe that Lestat covets mortal humanity the way Louis and Claudia (specifically the aging part for her) do. It becomes a mere comedy romp for him and a chance to get laid (Anne's vampires, contrary to fanfiction, a very popular misconception about the sexual content in the series that isn't there and the new series, are completely and utterly non-functional).
Anne Rice wrote and published IwtV in 1976 after the death of her 5-year-old daughter Michele from leukemia in 1972. The story came from a mother's grief for a daughter who would never grow up. Louis was, in fact, herself at her absolute lowest, while Lestat was her husband Stan (the character was originally named Lestan). Michele, of course, inspired Claudia. Madeleine the doll maker (note Anne's massive collection of antique dolls that surrounded her in her houses) was additionally another avatar of Anne.
Unfortunately, she became far too obsessed with the character she fancied inspired by her husband and wished to be more like. It's understandable, however, that it was too painful for her to write Louis, who was the character she had channeled her own grief through.
I've read the original quite a few times! I have read the first four books and have an idea of what is in the rest, though.