I have used the commercial containers you mention extensively over the past several years, primarily on trips to the Channel Islands.  My experience has been that both the one gallon and 2 1/2 gallon containers are too fragile for any critical use.  We often checked with the supermarket staff and obtained our 2 1/2 gal containers still in the cardboard shipping container, two per box.  Tthey travel much better that way, although you are looking at about a 43 pound package.<br><br>Much better are various gallon containers for fruit juice and Gatorade which are much sturdier.  These recycle very nicely.  For larger sizes I have broken down and bought commercial containers - these sometimes have features (like plastic spigots) which justify the extra expense.  I stay away from anything over five gallons if I contemplate moving it.  A three gallon container is much better for portability, at least for me.