I know this is an old thread but Modernbill is actually in Beta tests for its new release (v5) and WE are beta testers :D
I will definitly advice Modernbill to any new-comers into the Webhosting Industry.
Depending, of course, of what are your needs and your budget.
But, IMHO, MB is absolutly the best solution for small-mid companies who want a reliable (and robust) system to manage Webhosting account and bills.

As, said otherwhere, Modernbill is already far beyond any its competitors and will confirm its advance with this new release. Of course this is a bit early to say all this but, as far i could test it, this v5 seems to be really promising.

To be continued....