What makes a book publishing service truly worth trusting?

[jonathanmyers]

I've been circling around the idea of using a publishing service for a while now, and the more I research, the harder the decision feels. Some experiences I've read sound great, others sound like money quietly disappeared. So I'm asking here which book publishing service actually respected your timeline, your rights, and your creative vision, and how did you find them? Where do first-time authors usually get it wrong? Honest stories only, please.