In the seller point of view, I like annual billing, but most of my customers are looking for a quarterly(3 months) or an half-yearly(6 months) accounts. And if I ask them to enroll for an annual subscription, they never do !
Our people has become more shrewed nowadays and they never believe in people. More worse is a hosting reseller. But now I have some name among my customers for my best service and quick response to their questions.
So we the sellers like annual billing, but only a few customers agree with us.