I think it depends on your kitchen layout.
With our kitchen, we put the gas range on our island,I dont think it would look proper to have oven and range in the island. Our double oven is a built-in in the corner of the kitchen.
Hope that helps!

Yes it does depend on the layout. The kitchen in our home is fairly large (28X18) with a 10' island. We installed the double wall ovens at the end of a run of wall cabinets and we put a 36" gas cooktop and a prep sink on the opposite ends of the island. This works great since both of us often cook together.

At our vacation home the kitchen is quite small and we installed both the gas cooktop and wall oven in the island. The island is about 7' and we put the single 30" wall oven under the counter at one end and the 36" gas cooktop at the other. I like having two separate appliances- if someone is working at the cooktop you don't have to ask them to move to open the oven and you're also not standing in front of a oven venting warm air into the room. It's also handy if your oven has to have the door open part way when broiling.

I think layout is one of the primary deciding factors. We actually chose a Dacor 36'' cooktop with telescoping downdraft in our island with a Monogram 30'' oven in the island off to the side and an Advantium in the perimeter above the pantry pull-outs. It works for us.

I liked the idea of having a gas cooktop and an electric convection oven and many of the duel-fuel ranges I looked at were very expensive.

I also wanted a 36'' cooktop, but didn't really need a 36'' oven (just a 30''), so I saved some space but splitting it up.

Additionally, I wanted to use a telescoping downdraft instead of an overhead hood and most manufacturer's only approve downdraft ventilation for cooktops and not ranges.

We're very happy with all of the appliance choices we made. They work for us. Choosing what works for you involves identifying your needs and wants and picking what works best for you and your layout.

Good luck! :)

There's also function. Range ovens are lower than wall ovens, and under the cooktop mounted wall ovens are lower than range ovens. Lower=harder to access, especially for most people. Also, even though ovens are better insulated than they used to be, they do still have warmth on the outside, and you don't have to stand in front of the heat if you have wall ovens. But they don't seem to make oven ventilators any more, so having a range/below cooktop oven, lets you take advantage of a large vent hood for oven effluent as well as stovetop.

Ranges give you a focal point for the room, especially fancy ones. Cooktops give you a sleek look, and the ability to store your pots underneath.