I was looking at it from a housing situation where you could house many more quail in a stackable cage set-up for any given building size. If you've got lots of land, it's probably not an issue, but if you need to move them indoors for the winter, there's a definite advantage. The less they can run around, the faster they'll gain weight, but I'm not sure if that's much of an issue with your set-up.
If you've got a system that works for you, stick with it. If you want to, you can always experiment with other methods, but never give up a proven production strategy for a new idea until you've seen that it works.
I'm toying with the idea of tractoring them around when the good weather gets here, but I think I could only do that when raising them out as the layers might stop laying. I've also got such a small amount of land that I'm not sure if it's worth it if I want to keep them off the same patch for 60-90 days. I'm sold on the benefits of pasture raising, but I think predators would be an issue for me at night as I can't fence off an area to move them around in.
I'd try tractoring some of your next batch of meaties and see if there's a significant feed cost savings or taste difference. It would be a 4-5 week commitment to moving them once or twice a day, but you might find it worthwhile from either a cost or taste standpoint.