From one who doesn't do fractals (don't know how!) I'll say what I think.
I think the number is fine and in my opinion you don't need any more. I love the pattern in the big one and wonder if that's possible in the smaller ones? They seem a little dull in comparison and are both the same colour, which somehow disturbs me. I think the floor would benefit from being lighter, to accentuate the shadows and 3D effect. The stripes on the wall behind tend to take my eye out of the frame rather than coming in (like sun rays?).
Anyway, this is how I feel about the image and how it might be changed to create a different atmosphere.
I guess you could say though, that it pulled me in to look - so I like the concept a lot!

Firsty you got my admiration as I`m far to lazy to put in this amount of work. All the shaddows and light seem to be pretty much bang on. I don`t mind the floor or rear at all. The thing I would say is I think the two smaller spheres would have benifited by putting the fracs in the larger sphere into them as well. I think this would have gave a better feel of the spheres reflecting something the same and making it look more natural. That being said I think you`ve done a really good job.

Ian :)

Wow! Very creative. My mind doesn't work like that.
Great color and perspective.

Interesting creation, with equally interesting colors and composition. To my eye I prefer the large marble without the other two.