They all kinda suck it seems in some way. I'm working with PaySimple now and the service has been pretty nice, but it was a lot of paperwork and hassle, and now the effort in using the API..

I just looked at ClickBank. http://www.clickbank.com/recurring_billing.html

They were the defacto standard of people selling ebooks, but now they look like they have a recurring option. Their commission is higher I'm sure than a merchant account + gateway, and you have to use their credit card form, but it's probably the easiest to setup and lowest setup fees.