Most providers who sell reseller hosting packages, enable overselling...which really should be watched out for. Now with that being said, when providers oversell, most seem to think that it is an extra feature...but really it's mis-leading to the customer. With the "extra value" they feel they can charge more for. On the other hand you have decent providers that have a good network, excellent support, and unmatched service, well they have overhead costs which they have to make up for providing that great support, service and network, in return high costs for the consumer.