I know of people who prefer night float, and those who prefer traditional call. Personally, I did both as a med student, and I ended up going with a program that does Q5 traditional call.
The pluses of night float are, as people mentioned, you only have to do overnight call on Fri and Sat. You get to go home and sleep in your bed every night. What I didn't like about night float is that when you are on call, you are in such a rush to finish up your work and get done at a decent time, so that you can get home and sleep, because you have to come in for a full day's work the next day. Many times, we wouldn't get done until after 10 pm, and by ACGME rules, you have to be gone for 10 hours before coming back to work, but there is no way you can show up for work at 8am the next morning. That's way too late. Also, I hated picking up admissions from night float in the morning and trying to learn about them all before rounds.
In my program, we take call as a team, and it builds a lot of commradery taking overnight call with your team. Some of my most memorable moments during residency so far have been messing/joking around with my colleagues in the middle of the night. Plus, if I'm able to get 3-4 hours of sleep (which is usually possible in my program), I can go home post-call, take an hour nap, and still have the rest of the day to enjoy. In my program, we have a day float team so that we can get out by noon post-call (they finish up any of our work that we were unable to get to).