We do 4 day 40 hours weeks in the summer. It isn't that bad but it does get a little long. Most do 4-3 but we were doing a two week cycle of 4 (MTWH) on, 4 off, 4 (TWHF) on, 2 off.
Given that 8 hour workdays generally seem to involve a fair amount of faffing, and a fair number of people report diminishing returns beyond about 6 hours, what are those 10 hour days like? Does the expectation of a long weekend get everyone fired up, or do the last couple of hours really drag?
Weirdly, what time I eat lunch was the determinate of the day dragging. Noon or earlier and the day dragged. I'm off this week so I cannot give you a live feel today.
Yeah, it's basically very little off time for 4 days, but multiple 4 day weekends for the summer was worth it. Difference in sunset times would make this problematic in winter.