Weight wise, how much can be stacked. Looking for odt reviews. I have some that have fallen apart with not much wt on them.
I have a few that easily have 50 lbs + of cables in them and they do fine without sagging. They have a chart that tells you what each of them will hold and how many you can stack by weight. I think it's 5 high on the shorter ones.
Most of mine are the 21x15 footprint, so they fit through a regular door stacked on a dolly.