I published one of my books to Kobo last night as a test run. The process of signing up and publishing content is incredibly simple and straight-forward. It's slightly more streamlined than Amazon and BN publishing. And then there's Apple...
I don't know how sales will be but it's only going to take about five minutes a book to get my content listed there. I abandoned Apple after my test run. Their process was totally unsupported and annoying. It took four months to go through the sign-up and get the title approved. I even had to buy an old Mac for the sole purpose of publishing to Apple. All that and I haven't seen a single iTunes sale.