Sheet Metal Fabrication vs. Using Channel

[TheModMaster8]

Sheet metal frames allow you have a much lighter but equally strong chassy/robot compared to slotted tube, however sheet metal is harder to fabricate (bending it correctly) and can be dented easer, though i would definitely use sheet metal if i ever get the chance.

also note that by making the base out of sheet metal you have also move the robot/s center of mass much higher, thus making it more flip prone.