You'll always be able to contribute more to an individual 401(k) than to a SEP-IRA because employee elective deferrals are permitted to the 401(k) in addition to employer contribution. Unless the SEP plan as a SARSEP established before 1997, SEP plans permit only the employer contribution. The trade-off is that the individual 401(k) takes a bit more work to establish and manage and must be established before the end of the year for which you will be making contributions. On the other hand, a SEP plan can be established anytime up until the due date of the tax return for the year for which the contribution is being made.
