Problem with ACH is you have to cancel your bank account to stop withdrawals. There are horror stories of people getting fired and being unable to stop ACH with

Problem with ACH is you have to cancel your bank account to stop withdrawals. There are horror stories of people getting fired and being unable to stop ACH withdrawals (I'd rather my rent bounce this month than not be able to eat, etc) and ending up hosed. With a card you can just cancel the card number. It's best to use your bank's bill pay (push) instead of any external automated billing (pull).