A Professional / Enterprise subscription is the standard licensing option for companies, organizations and business entities. They can be used by any person/assignee within the organization.
A personal subscription can be used by private individuals, who wish to purchase a subscription with their own funds, and solely for their own personal use. Personal subscriptions are not to be purchased, reimbursed or in any way financed by companies, but can be used both at home and at work.
Professional and Enterprise accounts enjoy better support SLA times, dedicated managers, feature requests, training etc.