Which 27 inch double oven?
It depends on what you want to do. I would in fact consider purchasing separates instead of a double. In my case I am doing a bosch oven and a separate convection microwave. I am also going with a Capital Culinarian gas range with gas oven.
The major difference you will find is finish and some of them will have the option of steam. If you are a baker go with one of the steam ovens.
Have you considered Electrolux? It bakes very evenly, preheats in 7 minutes and compares very favorably with the oven in my Wolf range.
Have you seen the appliance forum on Gardenweb? It might be helpful to search those brands there.