As an aside, be careful not to make the assumption that night float = less intense.
Night float sounds wonderful when you hear about it from a flyer, website, or program director on your interview day, but if you talk to truly honest residents about their experiences with it, I've found that feelings are quite mixed (many people hate it, actually).
For one, the hours can actually be worse. If you're supposed to leave the hospital at 10pm, it's not unusual to actually leave at or 12 or 1am instead, especially early on in the year when you're less effiient. Then you still have to be there at 6:30 the next morning, and work a full day. So instead of just doing 28-30hrs of straight call but being off the next day, you work an 18hr day, sleep 4-5 hrs if you're lucky, then come back and work another full 12-14hr day. It's still about as many hours worked per 48hrs, but it's a much smaller block of time with which to recover. At many programs, night float also = much longer days and often no weekdays off. This can actually be worse for family, as you may be gone from 7-7 every day, and get home after your kid is in bed each night. This also makes it tough to get any sort of personal business done (haircuts, banking, dry cleaning, etc.), since you may never leave the hospital during normal business hours. To the contrary, a traditional q4 overnight call schedule can get you out by 4pm pre-call, and days off during the week, plus a nice long 16+hr block of time to recover post-call.
Many night float schedules also entail more weekend and night coverage when you're on what should be an easier clinic rotation. So instead of working a couple intense 70-80hr/wk blocks followed by a nice 45hr/wk clinic month, you might have 65-70hr/wk rotations for 11 months a year.
It's definitely a trade off, so you have to figure out what's most important to you, and what type of a system fits your learning style. Personally, I didn't want to be handing off patients I just admitted to someone else, as I felt that the first 12hrs was the most critical and informative time in a patient's care, and I wanted to be there to learn from those experiences. I also didn't want to be inheriting patients I didn't admit when I came in the next day, which is quite common in a float system. So I thought of overnight call as a good thing for intern year. Some systems thus have maintained intern overnight call, but utilize night float only for junior/senior residents.
...something to think about...