Would you rather work at 6-2:30 or 9-5?

If you're a person who's capable of getting used to getting up early, the former for sure. You'll have to make far fewer tradeoffs around the kinds of things you want to do outside of work (excluding going out really late at night on weekdays). Think about how nice it'd be to have sunlight after work

9-5 for sure. There are a few reasons why I'd do it.

Physical: Getting up at 4:30AM everyday may sound easy on paper, but research shows that light has a direct influence on your biological clock. Even if you sleep early it's always going to be more difficult than getting up at 7:30AM. 

Social: If you're targeting 7 hours of sleep a day you'd have to sleep at 9:30PM. 8 hours and now you're at 8:30 PM! Most people would have got off work, hit the gym and just finished dinner by that point and now at the time they are ready to socialize, hang out with you or even give a call or text you're already fast asleep. It's one thing to give up on the social life some if you're being compensated for it or working in a job that will pay dividends down the road. It's another thing to be working a standard 40 hour job and still having a poor social life. 

Is this Boeing?

I used to work in West Coast ER and hours were 5:30am - 6pm on a good day and 5am - 10:30/11pm on a bad day.

I'd rather do 6am-2:30pm. 

The earlier the better. I have no issues waking up early, naturally my eyes open around four, or where ever there is Sun light.

7-3 or 6-2 is the best.  Those last few hours of the afternoon take forever.  

Why is it 6-2:30?  Why does one schedule have longer hours?