Just a bit of feedback on your test forms: Your credit card number doesn't chunk the credit card into segments, making the input really difficult. And the sliding text when fields get focused is distracting.
Also as a question. Does my subdomain have to be nickw.easybill.co or will it be specific to my account? (not clearly stated)
Site looks great-
Hate to tell you though, I beat you to it by a few months :)
http://easybill.co
Different pricing structure. Driving keyword traffic has been a bit of a challenge. I think that this is a tough value prop for customers.
Overall, site looks great, wish you the best with it.