We use our camp ovens quite a lot and we have both Cast Iron and Spun Steel. I think there are good and bad points for both.
Spun Steel is lighter and you can't crack it, but if it is windy or a cold wind it loses its heat very easily, and likewise it will also crank the heat up very easy so you need to be more vigilant at heat control.
Cast Iron can crack if mistreated (although I have never damaged mine) but it is far more forgiving with the heat control. It has a more even heat and holds it heat better.
Both our spun steel and cast iron ovens fit inside each other if you buy the sizes to do that so storage is the same except for the weight.
They both need to be looked after or well seasoned as they will both rust if not treated well.
So having used both quite a lot, I prefer to use cast iron. Tassie gets a cold breeze at times so you need to shelter the spun steel oven and constantly keep an eye on the temperature when its like this.
Our really large family oven is spun steel for its lighter weight so its a keeper but the smaller ones are cast iron in our kit.
As for quality of cast iron ovens I cant really comment because I have nothing to compare, but for us we have always used the cheaper priced ovens and they have been really good to us. I can see why people would buy the dearer well known Aussie made brands though.
For me its not so much about the quality or price of the oven, its more so about getting the experience using the oven you have.