It all depends on what you prefer, but I recently was faced with the same issue and decided to take the job with the week-day 8 hour shifts. For one thing, it sounds like your Monday-Friday job will be at an outpatient facility since its closed on weekends and holidays?? The job I recently accepted is also an outpatient facility and I really liked the idea of getting out of the hospital setting....12 hour shifts at a crazy hospital just got to be too much after a few years. Plus, on those three days that you work for 12 hours (which is really about 14 hours by the time you get home after work), you get home too late and too exhausted to do anything after work, so at least when you work from 8-4:30, you can come home and still enjoy dinner with your family or something. I love my new hours, it's not as crazy of a job, I'm home on every weekend and holiday along with all of my friends and family, and on my days at work, the days fly by and I come home still energized.