Which Would You Rather?

Would you rather work full time, 12 hour shifts (day and night rotations 50/50)
or
8 hour shifts full time, (day and evenings)?

And why?
I pick 12s over 8s every time although I actually loved the evening shift 3p-11p. I just can't stand to work the same place 5 days in a row. Now if I could work 3-8s on evenings and make my full time salary that would be my dream job.