To see what improvements I was getting in exchange for the arm and leg the new oven cost me, I baked the usual 3 x 1Kg white loaves.
The two most obvious improvements are first, the elimination of "Hot spots" in the oven which enabled me to get an even overall browning without having to turn the loaves part way during the baking, and secondly the elimination of hot spots gave an even overall heat which in turn gave me a very even spring without the usual bursts in spots. I was able to put the loaves (two at a time) in the oven, 1 spray, 6 ice cubes in a dish on the bottom shelf, shut the door and forget it. Well I didn't actually forget it I stood there and watched the whole process.
What is not so obvious is the improvement in crust, particularly on the bottom of the loaf. I used to get a thick hard bottom crust, but now the bottom has the same texture as the rest of the crust, just nice and firmly crunchy.
The overall improvement is due to the difference in the cooking methods.
In the old oven all the heat was coming from an element sitting at the bottom of the oven and just relying on natural convection to distribute the heat. Now if you combine that with the fact that the oven insulation was very poor (hot cupboards surrounding it), it meant that the bottom element was running quite often and radiating a lot of heat onto the bottom stone and the rest of the oven was just taking pot luck.
The new method is called "Fan Bake" (not fan forced, I'll explain later) and the heat comes from the outer edges of the top element, and the bottom element which is under the oven floor, this heat is then distributed by the oven fan which draws the hot air in and blows it out around the four sides of the oven, thus giving an even heat throughout the oven.
In this oven "Fan Forced" is where the fan blows hot air from a separate element surrounding the fan.
The photos don't really tell the story, you would have to have tasted and seen the old and the new to really appreciate the difference. All in all a very worthwhile investment.