Am I better off with a 401k, or a Roth IRA?
I would say always take advantage of the full company match for the 401K. Then whether you use the 401K and traditional IRA or the Roth IRA depends on your diligence in the past and the amount you have already saved. It originally was true that most people could pay taxes in a lower bracket on 401K and traditional IRA withdrawals at retirement; however, diligent savers may find that they may be forced to pay higher taxes at retirement. If you have been very diligent in the past or have a long time until retirement, the Roth IRA may be best as (while there are no deductions at present) the withdrawals are tax-free at retirement. It’s great that you are planning ahead!
