I plan to purchase a rotating rack oven for my bakery. What type (gas or electric) would achieve the best result for pastries and small breads?
Electric is generally better for baking. Gas ovens introduce a bit of water vapor due to the combustion of the gas. In general, electric ovens also have smaller variations in temperature during the oven cycle than gas, and so maintain a more even heat.
In forty years of baking I have used gas, electric and oil fired ovens and I can tell you that the construction of the oven matters more than the fuel. I prefer gas to electricity, mainly because I need a smaller generator to keep a gas oven running in case of a power failure. (I have the stand-by generator to keep the lights on for employee safety, but if it helps me finish what is in the oven at the moment, and keep the refrigeration running -- it is a strong plus.)
Frankly, all five ovens here run on gas because gas is cheaper then electricity here, and our ovens do excellent jobs making bread, pastry, cookies, pies and cakes. Our two and four rack ovens are from Gemini, two 24 pan rotary ovens from Fish and our conveyer oven is from Picard.