I'll echo same comments as others.

Being able to stack them in a storage shed without them falling over is another strong point. We stack them 2-high all the time, though I'm not real sure of their stack-limit. All of our corn & beans come in pb, except for a few odd-bag numbers.

We've also loaded boxes w/conventional paper bags. Also, since we find that occasionally we have to take "odd bag" assortments (like 23 bags for example), we'll take one box & when it's empty, remove the upper 1/2 (just twist the handle locks) & leave it on the 5th wheel & dump bags into it. You can "hinge" the lid on it with h.d. tyes. It's then just about the right height to dump bags in to, assuming you even have to do that.

We've had 0.0 problem w/rodents. The only minor "problem" we personally have is to make sure there is no gravel sitting on the probox framework that could fall into the blower funnels under the cradles. We check that just before we set the pb on the framework.

In this YouTube you can see our ProBox setup in use.

http://www.youtube.com/watch?v=lyhKb2S4jeQ