Group Iso = easy as hell to get. kind of a bitch to work with though... I have terrible credit and they gave me an account no problem.
others = intuit, npc = relatively easy.
Neither one is terribly hard to get. Best thing to do is state that your simply a web design company and that services are rendered before payment. Even throw up a simple website that lists like 2 or web packages and their prices (around what you will really be charging). SEO and recurring billing IS considered high risk by most merchant providers...
Had to do this a few times. Once your set up and your not getting chargebacks they don't ask you any questions or bother you about the fact that you have recurring billing set through authorize.net