If you mean the 'all blue' I tried them once and they were a disappointment.
I don't know what I was expecting, but the website below describes it best
"The flavor is remarkably normal for such a distinctively visual variety."
I'm don't think they can ship to the US but this is the best site I've found
up here for variety with a description and some decent pictures of what
potatoes are out there. I think the "sold out" is just there way of turning
off orders.