I work 7p - 7a 3 days a week and have for the past 8 years. My kids are grown and only have 1 living at home so being able to sleep isn't a huge deal for me. Have worked a set schedule, a schedule where it varied from week to week and it's alot easier if you have a set schedule cause your body can somewhat adjust to it easier imo. Even doing it as long as I have I still go through periods of feeling like hammered dog shit. Usually only happens about once every 3-4 months. Working 7 on then 7 off will have it's advantages which have all been mentioned in here, but for your first couple days off you probably still won't feel right unless you maintain a night shift schedule on your days off. I have seen people do that, it works for some, kinda just depends on your lifestyle.
Night shifts aren't for everybody, have seen some really try and they were miserable no matter how much sleep they got during the day. Personally I really like it and would probably have a hard time going to a day shift now.