I've had my brushes like the top picture for a while. I loved the way it looked, but the shells scratched up my brushes. :( I didn't think it would because they aren't sharp. I guess since they are a harder material, it makes for easier scratching.
I decided to get those plastic vase fillers like everyone else has for their brushes. I like this method a lot better, even though it's not as pretty. My brushes slide in and out a lot easier and I don't have to worry about it damaging my brushes. So, if you're looking for a way to store your brushes, I'd choose the second method! :)