The fastfold oven is very well built overall but I would like to see several changes.
#1. The fasteners are too light duty. It would be nice with such a tough rugged built oven if the fasteners were also rugged and tough.
#2. I would like to see the ability to change levels of the two shelves as at times they are just not in the right spot for optimum usage.
#3. With the stove produced heat having direct access to the base of cooking vessels, there is somewhat a tendency to burn the bottom of the foods being baked. If there was a feature built in that caused the heat to not have direct access to the cooking vessels but instead had to go around a heat "baffle" there might be better overall thermal distribution. However perhaps that might cut back on the maximum heat that the oven is able to achieve.
Overall the oven is very well built and should last for many years. It is a joy to use and to be able to bake great foods when in the backcountry is awesome.