There is no reason to add powder coating to stainless steel as it adds cost and additional prep steps to provide a surface for the powder to adhere. Likely the cage is traditional steel.
If I recall correctly, Prevue manufactures much of their product line in China in one of the two facilities that are still making cages.
All Stainless Steel is not the same! There are grades, which defines their market /application. (Web search Stainless Steel Grades for greater detail) Another factor that comes into play is the thickness of the bars used, the spacing, and the number of cross bars used. Finally, what effort is placed into buffing the welds and the cage faces to provide the shine. It all adds up to define the cost of the cage.
Regard cage design, select the cage that provides a full front opening door (top to bottom) as it will make your life much easier. Traditional rectangle provides the greatest space and ease cleaning. The flat top provides for the addition of a play /perch area. Not as pretty as other styles but provides vertical usable space.
FYI: Buy extra water and food bowls with the cage. Finding replacements a few years later becomes very difficult!!!
On a side note, IMHO, being able to quickly roll the cage out the door(s) in an emergency has merit, also its easier too deep clean a cage outside. So measure the doors and allow for a bit a wiggle room and keep the depth of the cage under that measurement.
FYI 2: Unless you are near the ocean, there is little need to buy Stainless Steel as the primary reason to buy Stainless Steel is greatly to totally avoid rusting. Once one is 20 to 30 miles inland there is limited concern if any to be concern regarding salt in the air.
