Well, I have the Cannabis Grow Bible, and it says 24/0 is better. But, being from the Show Me State, I did decide to test it to be sure. So, I got 12 clones from the same mother. I happened to have two exactly identical small cabinets, so I put 6 plants in each one, ran one box 24/0 and the other 18/6. After a month, the 24/0 plants were quite noticeably larger and bushier than the six 18/6 plants. So, I stopped the experiment right there, figured that I'd seen enough for myself, and the Grow Bible's information was correct. And I've been 24/0 ever since.
The increased hermie thing is sort of a myth. The reason why 24/0 can cause more hermies actually has nothing to do with the light schedule, at least not directly. It has to do with heat. If you leave your lights on 24/0 and don't have adequate ventilation, then you get too much heat, and THAT results in more hermies. It's not the light schedule, it's the heat. If you have adequate ventilation, and have your temps well under control, then you won't have that problem; I've been 24/0 for years, but I keep my temps under control, no heat buildup, and thus have never had any hermie problems. If you need that 6-hour cooldown window because of inadequate ventilation, then that's life, and you should be 18/6, just to keep the temps under control. Otherwise, they just grow slower with less energy available to them.