There’s a good article at MLV Writes on self-publishing, titled THREE REASONS TO SELF PUBLISH (AND A BIG ONE NOT TO!). I’m linking to this here not only because we encounter many authors who are considering self publishing, but also because the first three reasons are often involved in choosing a small publisher rather than a large one.
In addition, the big reason not to self publish—to avoid all the hard work of traditional publishing—is also not a good reason to go to a small publisher. If your small publisher doesn’t go through all the hard work, you’re getting less than you should. On the other hand it can be easier to go through all of that hard work with more personal attention, though the extent of that personal attention depends on the particular small publisher.
In any case, the article contains some good advice.
(Energion Publications offers a form of assisted self publishing via our EnerPower Press imprint, which is designed for specialized projects that don’t fit one of the many nearly automated options for getting your book printed.)