There is someone on a thread who has owned both a La CornuFe and a Lancanche and seemed to like both equally. You might dig around for that post.

Certain AGAs stay on all the time, which would explain them radiating heat when not in use. The Lacanche does not and I haven't ever heard of it radiating heat when not in use.

Have you seen and cooked on both? If not, you might consider doing so. Performance is in the eye of the beholder.

The only reason a Lacanche might "radiate quite a bit of heat even when not in use" would be if one was using a Lacanche equipped with a French plate; just as it takes some time to heat-up a French plate, it takes awhile to cool down the French plate after use. Of course, every Lacanche does not come equipped with a French plate ... it's your choice.

Gigi7 has owned both a Cornufe and a Lacanche and is pleased with both... her very helpful assessment is linked below.

I have a CornuFe 90 (Albertine) and I'm very pleased with it -- my review is somewhere here.

The AGA Legacy line is a US style dual-fuel range -- it does not radiate heat like a traditional AGA but has some of that traditional styling. However, I have not cooked on either of the two, so I can't comment on the performance.

BTW, you can get the CornuFe from your local dealer as well, which may be willing to do a package deal with your other appliance purchases.

Here is a link that might be useful: Old Thread with Gigi7.

Personally if I lived in Texas (I did for two years) I'd get a Lancanche for the smaller ovens they have. One of the fastest ways to heat up a kitchen is the oven and a 36" oven is quite large. Although I think when I looked at the Le Cornufe the oven was the size of a 30" oven. Nevertheless the 21" and smaller ovens on the Lancanche would probably heat up way more quickly than these bigger ovens and cool down more quickly, keeping your room cooler overall. But of course I just bought a Lancanche so prefer it over the Le Cornufe. Also, per Trinkette's excellent point, I would not get a french plate if I lived in TX. Good luck!

I used two different gas Aga's will living in England for a few years. In the first house, there was nothing other than the Aga for cooking, so it had to stay on all year long. Even with the temperate English weather, it made the entire kitchen and areas surrounding the kitchen very hot during the warmer months.

In the second house, I had a separate oven and hob (range top), and I was advised to turn the Aga off during the warmer months. This is
however,not recommended here in the USA. The Aga representative I spoke with here, said it will cause the unit to rust. I live in Michigan and although it would be wonderful for our winters, it just gets too hot here to
consider leaving it on all year long.

After adjusting to the differences of the Aga, two large burners and
small ovens, I came to love it. It is a solid piece of equipment. The ovens
though smaller, cook foods beautifully. And it could hold everything I cooked for my family of six plus guests even on the my biggest cooking
day. The two burners are large and can hold several pots at once. They are set at two temperatures, boiling and simmer. I never found this to be
an issue. It was great being able to put a pot of water on and have it at
rolling boil within a few minutes. The top of the unit (actually the whole unit) is extremely warm/hot so butter, etc. could be melted in a bowl just on the top.

I seriously considered the Aga Legacy, but after seeing it in person and
reading many reviews about it, I decided it wasn't what I was looking for in a range. I also considered the La Cornufe CornuFe' but I learned it was
owned by Aga Rangemaster. I have seen it in person a few times and it just doesn't impress me. Neither the Legacy or the CornuFe' felt as solid as the original AGA.

I have decided on the Lacanche range, most likely the Cluny 1400. I like
that can configure the ovens and stove top to my specifications. And I
believe the small ovens will work similarly to those of the 4 oven, gas Aga. I used the warming oven in the Aga to make many slow cooked meals and I plan to do the same with the warming cupboard on the Lacanche. I
have also read reviews on this range going back years and it is extremely
well reviewed by most everyone who owns it. I found many of the older reviews are under blogspot just by searching by Lacanche.

Good luck with decision!