Complicating all of this is the issue of commuting. One of the major benefits claimed for the 4-10 system is that a worker has to do only 4/5 of the commuting as on a 5-8, and the time and money thus saved may make the shorter week advantageous for some people who would otherwise not prefer it. Nevertheless, commuting may exacerbate the pinch on the second shift during work days, since the worker is away from home for the 10 work hours plus perhaps two more hours of commuting. And working longer or weirder hours can be a major burden on people with limited access to transportation -- people who are disproportionately disadvantaged in other ways, e.g. poor and/or female. I can drive my car just as easily at 6 pm or 8, but someone reliant on a crappy public transportation system or shared vehicles may have a rougher time of it. The direction this points us in is that labor issues can't be solved entirely within the shop, through things like working hours. They also require looking at questions traditionally classified under environment or energy (or perhaps more accurately, what I'd call "landscape policy" -- questions of the physical and social layout of the spaces we live in). We live in a world that has -- in many cases through conscious policy, not just the unplanned output of the free market -- been physically laid out for the convenience of a certain type of relatively privileged person.
All of this is, of course, meant in the spirit of raising issues rather than proclaiming generalizations. Jobs and outside lives are far more diverse than usually assumed in thinking about how to arrange a just work system, so it would be wrong to state categorically something like "4-10s are bad for women." The point is to remind myself not to make assumptions that other people's lives are arranged like mine.
*Technically I worked a 5-9 then a 4-9, so I had an extra day off every other week.