I have seen the square cans blow corners out when they are not gently set down, also seem to be thinner and crack easier. The IMS round cans seem to hold up well, and when on your shoulder, the corner is not making the can awkward. Biggest thing i think is getting your crew to treat them with care as best possible.
And as mentioned above, whatever brand holds 13 gallons, yes it is a bit more fuel, but also heavier for people that are use to 11 gallons, to now add another 16 lbs of fuel it is shocking.