We have recently added some new features to customer subscriptions which you can offer your customers.
Making customers tax exempt when they sign up to a subscription.
Product limits - the ability to set product limits, so if a customer goes over the limit stated then the customer would be charged for this.
New payment scheduler - If a customer signs up to a subscription, they will be automatically charged via the payment processor you are set up with (Stripe/Clearent) and an invoice will be created. The invoice will appear as paid if the auto charge went through, if not it would appear as unpaid.