Spoiled for Choice
Once you decide self-publishing is for you, the next step is picking who to work with. Some will argue the existence of a divide between true self-publishing and old-fashioned vanity press; in my opinion, they're all just degrees of the same service. Whether it pertains to design, production, or marketing, the publisher you choose should be in direct relation to the amount of work you want to do yourself. That said, with the increased accessibility of self-publishing, the number of companies offering these services has multiplied accordingly. So how choose?
Looking at the combination of services offered versus pricing is a logical first step. Some will have this relatively well explained on their websites, others do not. If a company can't or won't fathom the importance of offering a comprehensive website, said company drops off my radar immediately. These are the people who will either prepare your product for sale, or ultimately sell it for you. Not having joined the 21st century is a non-starter.
Once you wade through the remaining price/product comparison you're likely to be down to a few competitors. To narrow the field even further, I ordered a few of their finished products (or received a returnable sample) to verify the actual quality and scoured the internet for complaints or reviews of the company in general. Complaints are never hard to find on the internet, but they should be taken with a grain of salt and are more often than not spawned by personal grudges and ignorance more so than meaningful concerns.
One such recurrent (and pointless) complaint is the need to pay for ISBN registry even though this happens in the publisher's name, not the author. This is not some hoodwinking technique. The ISBN is in essence an identifier used by publishers, booksellers and libraries for ordering and listing purposes. It is therefore unique to each and every book. Which means that if at some point you move your business elsewhere and have your book printed by another company, it will become a different "product" and therefore require a new ISBN anyway. Simply put: it doesn't matter one iota whose name it's under, you will be getting a new one for every iteration of your work.
As I whittled my way down to that final choice, one thing became increasingly clear: it doesn't matter who you have print your book. You're signing up for the fast-food production service of book selling. Find your editor elsewhere, and make sure your product is optimized long before you deal with any of them. Your expectations should be low where anything other than the actual printing is concerned. Marketing will be where your product fails or succeeds, and this alone should be the target for the bulk of your investment.
