There is little or no administrative expense. Earning on the account are not currently taxed. Participants have the right to direct investments. Participants can also have an IRA account, if income is below certain limits. Employees can withdraw the funds as fast as they are put into the account.
Employees usually control investments.
Employer may not adopt a SEP if it ever had installed a defined benefit plan. There are no guarantees as to future benefits. Investment risk rests on the participant. There is no assurance as to the frequency and amount of employer contributions. Lump-sum treatment of distributions is not available.