Hiya, I have tried the Egerie with the extended soundboard. It sounds big. A bit like a bell. The base is very resonant but overall its well balanced. I tried it in comparison with the extended Salvi Daphne and the Lyon&Healy Chicago extended and it blew both of them out of the water.
You may want to consider how you are going to use the harp. I went for the Egerie with the straight soundboard because I will be mostly playing in my small apartment but if you want to play in larger spaces or in an orchestra the extended soundboard will sound lovely.

You might have heard it a thousand times already but every harp sounds different. I tried four different Egeries with an extended soundboard and six with a straight and even though they all sound good there are noticeable differences between each individual harp.

Did you see the video on the Camac youtube channel? Sylvan Blassel plays several works from Hayden and Beethoven on an Egerie. The extended soundboard one sounds bigger but it gives a good impression of the sound profile of the model in general.