We love our Sun Oven for its compactness (when folded for storage) light weight, and ease of use! It works great, we use it almost daily in the Sunny months and have made everything from rice to roasts, muffins to cakes. We bought our first Sun Oven back before Amazon.com existed, and like it so much we got another. Keeps the house cool and the utility bill down in summer, too ;)
Preheat it before putting the food in. Aim it a little ahead of where you need it for longest solar impact.