In the romance market, there are still a few options for the unagented author (and for the purpose of this post, I'm ignoring e-publishing, which for the most do not require agented submissions). Most noticeably, M&B, and from what I've heard, having an agent doesn't improve your chances or waiting times.
If you want to submit to Harlequin or Avon without an agent you have to take your chances with a query letter and synopsis, and if you suck at that, well, no way to get your first couple of pages before an editor's eye. Dorchester and Source Books are an option, but you're going to go straight into the slush pile and unless you catch an editor on a really boring day, your submission will get processed by a sush pile reader first and not an editor. Tor accepts an unagented partial for science fiction submissions.
The good news is, authors can, and do, get picked out of the slush pile. The bad news is, I've seen a steady decrease in publishers who accept unagented submissions and as the rate of submissions increase alarmingly (this has been reported in the last two years) I fear more and more publishers will want to flush out their slush. (Ooh, that rhymes)
An interesting aside: Even publishers like Harlequin and Sourcebooks are now requiring agented submissions for their young adult lines.
Well, I've done the submission rounds plenty, to both agents and publishers, and at times it feels like it's definitely more difficult to get an agent than to get published.
And here's my personal thoughts on why:
An editor just needs to like the book.
An agent needs to like the book, plus she needs to think of a number of editors she has a connection with who'd also like the book. She has to consider the time and money she'll spend and the possibility that she won't be able to place the book.
An editor doesn't really care about your publishing career - unless you become a bestselling author and then you've got her interest. But they have a large number of debut authors that get lost in the woodwork and disappear.
An agent is not investing in a single book - the good agents are investing in your career and committing to stick with you (for at least a couple more books)
An editor doesn't need to know much about you as a person or even like you.
A good agent wants to feel a connection with authors she takes on. No need to be best friends, but you and your agent have to like each other, be able to communicate well and have similar goals. Some agents want to meet before they'll consider signing you.
A publishing house never has a closed list (unless they're going out of business)
Agents do. And the most frustrating thing is, most of them don't let you know. They keep the query door open, just in case the next JK Rowling knocks, but in general they're not really looking and thanks to form rejections, you'll never know if they really didn't like your book or if their list is just full right now.
On the upside, there are only a couple of publishers out there while there are hundreds upon hundreds of agents, so it might take a little longer, you might need to grow a couple more inches of thick skin for all those hundreds of rejections, but the odds hopefully balance out somewhere down the line.
What are you writing and to whom are you submitting? Do you know of other publishing houses accepting unagented submissions and do you have any advice, feedback? Any and all thoughts welcome.