We went to nightfloat at our main hospital last summer. I cannot say that I like it. We used to have 24+hr (usually came in 0530-0600-ish, left 0700 after morning report) call every 5-7 nights (two residents), only ever had the two post-call residents out of the OR on any given day. With the new duty hours, we changed to a 1800-0700 nightfloat M-F (call attending arrives 1500), with 0600-0600 Sa/Su call. Some of the bad things about this are:
1) We don't have the overnight case volume to support it - Generally, the nightfloat team arrives, takes over some rooms, and finishes out the add-on cases, then the junior manages the Acute Pain Service as his primary responsibility (can be a massive headache, depending on which ward nurses are working), while the senior does preops and sleeps. Rarely do we have cases coming in the middle of the night, and the few that do are usually simple appys (80% of the time, nothing after 2200).
2) Being on nightfloat is a week out of the OR, and a week that you are not doing regular cases (some see this as a plus, though, as it can provide a break from the grind). Consequently, those on subspecialty months are not placed in the nightfloat pool (just weekend call, usually a Saturday).
3) Mondays are down four residents, rather than two (Sunday post-call pair, and the new nightfloat team)
4) People on PACU and Regional have to stay later. No more signing out to the call team at 1500-1600 and leaving, those residents now stay until the nightfloat comes on (sometimes the PACU resident will get released after 1700, if the call attending is actually willing to carry the pager for an hour).
5) NO POST CALL DAYS - With the old call schedule, we were generally guaranteed to have a couple of weekdays off each month to relax and take care of things at home (take the car to the shop, go to the post office, doctor's appointment, etc). With the nightfloat system, we get none, unless on nightfloat. But if you are on, and happen to get a case in the middle of the night (even a simple appy will ruin your night, as everyone is incredibly slow to get things rolling), it screws your week, as you never settle into a proper day/night rhythm, and have to come right back the following evening.
When I am at work, I want to work. If we were actually busy doing good cases throughout the night, I might feel different about nightfloat, but as it stands, I see it as an inefficient call system that interrupts my ability to do real/regular cases and sleep for a week.