You have $1000/month that you can
- invest in a guaranteed 4.375% account (paying off your loans early)
- invest in something else, e.g., stock funds that could increase 30%, or decrease 30%, or...?
- split among different investments
If the Roth IRA is completely separate from your employer (i.e., you opened your own investment account and are investing it yourself), then my $0.02 says "pay off the student loan".
If all your investments are through your employer, then I'd suggest opening your own Vanguard (or Fidelity or Schwab or ...) account (so you develop experience and comfort doing so), then putting $500 toward the loans and $500 into your iinvestment account.
In another few years you can put on your hindsight glasses and know for sure what you should have done....