Some people ask me why I narrate my own books, and I joke that it's because I'm too broke to hire someone else. The truth is, I enjoy it. I like giving voice to my characters. More than that, though, it's a final QA check. After the various drafts and editing, and beta readers, sometimes things still get missed. A sentence might be grammatically correct, but hearing it out loud might sound awkward. Even if I were to hire a narrator, I think I would still go through the process of reading it out loud anyway, just for that reason.
I've been told I'm a very good narrator by some, and I think the worse criticism I received was that I was "passible." You can't please everyone, but I work hard to improve with every book. For The Baby-Eater, I wanted the Filipino characters - which was almost all of them - to sound authentic. I studied the Filipino accent, took notes, and had my wife - my permanent in-house Filipina consultant - listen to my recording. She would coach me on Tagalog pronunciation, and sometimes I'd have her record lines for me to use as a reference. Considering the multiple awards that book won, I think it paid off. The new book is very different, but hopefully, I can maintain or even surpass the previous book's quality.