Well, I guess you do (generally) get what you pay for...
I liked that these drawers are width adjustable (essentially in three incremental steps,)
plus, at $30 apiece they offered a nice price point. Truth be told, the adjustable width is not well
engineered, with the side panels sagging excessively when extended beyond the narrow setting.
I therefore stiffened them up with compression clamps (primarily used for rope clamping) - see images.
Slide action is "O.K." - we'll see how my re-engineering holds up.