25' 30 amp extension cord

CA Traveler wrote:

Wire quality can be a concern. Copper coated aluminum for example.

Lower voltage can be a concern depending upon load, wire quality and pedestal voltage.

I don't think I've ever seen an AC extension cord with CCA wire. Jumper cables, for sure, but not extension cords. Anything UL approved would have the claimed gauge of wire used, though there may be differences in the quality of the jacketing or other construction details.

Voltage drop, assuming there is no fault such as a bad connection to the plug or socket, is a simple matter of the wire gauge, length, and current flowing through it. Of course with poor voltage at the pedestal one can reasonably tolerate much less voltage drop in the extension cord.

The main differences I see in prices/quality are in the connectors, somewhat less in the cable construction, and in the seller's or maker's markup/profit margin.