I had a few about a decade ago. I can't say that they really sounded any better, certainly didn't sound worse.
From a collector's standpoint, they are kind of neat. I think they might be worth collecting and the prices on some of these tells me that others feel the same. If you just looking to collect something that you don't see everyday, then go for it and $50 sounds about right. If you are looking for a vastly superior CD, then you will most likely be disappointed.
For reference, back when I did see these in the stores, they did sell for about double what a standard CD would be, about $25 to $30.