One significant difference, among several, is the leased employee feels more like an employee with a stronger connection to the employer. Leased employees also receive more benefits than temporary employees do. A temporary employee does not usually have a strong bond to the client company.
Leased employees are considered to be employees of the recipient organization for purposes of the requirements set forth in section 414(n)(3)(A) and (B), even though they are common law employees of the leasing organization, unless (i) they are covered by a safe harbor plan of the leasing organization, and (ii) leased ...
Leased employees may be eligible for benefits through the leasing agency that employs them.
Examples of work provided by Employee Leasing Companies are Payroll Services, Insurance, Tax Services, and various Personnel Services.
It is possible to draft your own lease agreement, but you are leaving yourself open to issues.
A PEO, or professional employer organization, has a different relationship with client companies. Instead of being a firm that leases employees to their clients, a PEO becomes an employer of record for the client's employees. This is known as a co-employment agreement.