+1
After forty years of bass playing, I've concluded that casters are necessary for any heavy bass cab (IMHO). I can't recall having any problems, and I've rolled over cobblestones, brick, etc. A hand cart can be great for transport, but useless if you need to reposition your rig after setting up onstage.
Be aware, though, that if you're installing removable (pop-out) casters, a large center hole must be drilled to accommodate the receptor cup. Make sure there is no bracing or screws from the original cab construction that are in the way.