I have and continue to use the bedourie (the second type you mention) oven.  I actually take both the bedourie oven and aluminun dutch oven on our Quetico trips.  You are right that it is multi-functional.  It does not work as well as the cast oven for the reason you mentioned (uneven heat distribution).  However, we often bake with it if the cast aluminum oven is being used as a fish fryer.  Again for best results, place the item you want to bake in a seperate pan and keep some air space between the pan and the bottom of the oven.

Thanks for the help with the spelling and origin of this versitle cooking device.