403(B) or Roth IRA For This Year?

Hello all, I am someone that has never really paid attention to investing and would like some advice regarding retirement savings options for this year.

I am a 26 yo single male with no dependents living in Oakland/San Francisco, California that's just about to enter work force as a medical resident. I will be paid around 58,000 over 1 year period starting July, and will average same amount for next 4-5 years after which the salary will likely significantly increase (let's say 250 k). Retirement is a long ways away, but I imagine I will want to stay in California.

My employer has a 403(b) plan that I can put money into, but they have 0 matching so the traditional advice to invest in 401k/403b until you at least use up matched amount does not seem applicable to me.

For 2017 calendar year, with moving stipend my total earnings will be about 31,000. If I want to invest around 10,000-18,000 overall towards retirement between 7/1/17-7/1/18, should I go with my employer's 403(b) or forego that and start a Roth IRA and contribute the maximum 5500?

After some (admittedly brief) research, I thought that the Roth IRA option makes more sense for the 2017 year given I will be earning about half of a normal resident salary and significantly less than I expect to be earning for the majority of my working career.

For 2017 year, should I focus on Roth IRA, traditional IRA, or 403b as my primary investment option given 0 employer matching and relatively low income bracket (31 k)?

Same question for rest of residency, where my yearly income will likely be around 60-65k.

Thank you for reading this rambling post and please let me know what you guys think.