I'm in the admissions ward and we do either 2 nights 3 off then another 2on/3off or a run of 3 each month it is absolutely non stop in our ward but I love it shifts just fly by, quite often a lot busier than the day shifts, the only bad thing that I've experienced is minor hallucinations due to tiredness at the end of the run of 3
(I'm unlucky this month, have 2x 3 runs of nights )