Since these are pre-tax contributions, I'll assume this is a 457(b) plan.

Now, whether to contribute to this or not really will have to do with your investment choices and the annual plan fees. Non-profit 457(b) plans have a bad reputation for the excessive fees and expensive, mediocre performing mutual funds the plan administrator (usually an insurance company) make available to plan contributers. You'll need to check on this.

If so, I think I'd pass on the 457 plan and contribute to your IRA.

 BruceM