Glass tanks (fish tanks) are very hard to keep humidity in. You can see the snakes better, but poor humidity is a bad tradeoff for that. If he wants a good display enclosure, a pvc cage for reptiles, like an AP t8 (animal plastics) would work. You can get a divider for the center so that you can house one snake on each end, but it is not cheap.

I use tubs right now and plan on getting a rack soon. I believe that as long as the tubs are large enough so that the snake can move around (and it'll fit a water bowl, rock, and a couple hides) it is just as good as a tank, and holds humidity better. The downside of tubs / racks is that they don't hold heat as well due tot he thinness of the plastic. I had to use heat lamps over my tubs to raise ambient temps, but now have all of the cages / tubs in a heated reptile room, which is a better solution.

Tubs / racks are easier to clean... Much easier compared to a glass tank, which is heavy and difficult to lift / wash.

Just a side note here, but I'd be very careful when you make plans to go off to school, so that you can move somewhere to take your snakes with you. Most on campus dorms do not allow pets (just something to consider).