I've actually had the pleasure or working on days in orientation for my first twelve weeks as an RN and then on nights in orientation for 6 weeks. Two different hospitals in two different states.
I have to say after my experience, I have enjoyed nights much better. On days, especially if your preceptor gets a normal patient load when they have a new grad with them as mine did (1:6 maybe 7), the preceptor is so busy with meds, calling doctors and social workers and discharge planners etc, getting admissions in, getting discharges out, changing dressings, emptying who-knows what that they don't have as much time to answer questions, to explain things, let you practice in your own time frame, observe activities other professionals on your unit perform to help you understand certain treatments for your patient.
On night shift, you have less family around, fewer doctors around, more time to research whatever you need to...not to say nights can't be hectic, just as hectic as days (yes, more codes do occur on nights) The only terrible downside is possibly a higher pt load if you don't work at my hospital (1:5 every shift on med/surg...HALLELUJIAH).
You do get more 'skills' experience on days if your preceptor has the time to actually follow you and let you learn and practice the skills....but if you come in on nights, ask all the nurses on your shift to let you know if anything interesting comes up that they think you may be interested in seeing or doing and you'll get tons of experience that way. I've gotten just as much experience with skills and assessments and even calling doctors (unfortunately) in my 6 weeks on nights with 1:5 pt load as I did in my 12 weeks on days with 1:6-7 pt load. And I've enjoyed the more calm atmosphere. It does a new nurse good to feel at least a scant amount of peace while at work, dontcha think?
Anyway..good luck with whichever shift you decide on...and if you decide on days I'll keep my fingers crossed for you (only a couple from my class actually got day shifts as new grads...and that was because they already worked at the facility as aides)