Oh, the Ibizan stories I could share, romansperson - none of them good. For starters, Ibizans aren’t really a “true” sighthound, though they’re classified that way in the U.S. In Spain they hunt in packs, as much by scent as sight, and that’s part of why they’re so incredibly barky. The males tend to be fighters with other males, too, and I know of more than one male Ibizan that was severely maimed or killed by fighting with other Ibizans.
Temperment problems used to be rife in the breed, although I know that after I left there were several people going back to Spain for more stock so that may - may - have improved. However, given that I’ve met one former resident of Ibiza and one then-current resident of Majorca who couldn’t believe anyone would keep one in a home (they’re usually semi-feral on the islands, although the dogs exported to America always did come from more typical pedigree kennels), maybe not.
But the big thing no one likes to tell prospective owners are the widespread genetic disorders. It’s an old familiar story - one extremely and justificably popular stud dog spread some defective genes for epilepsy and a breed-specific degenerative nerve disorder into a tiny gene pool. By the time anyone knew what happened, the breed was in terrible shape. Without pointing too many specific fingers, let’s just say that many of hte people active in the breed back then were far more interested in (and I quote) “making their name by showing and winning big” and “making an impact with their breeding program” than they were with breeding healthy sane dogs.
Has the situation changed? Don’t know, don’t care to find out. I can’t imagine that even the most committed, coordinated breeding program could have turned the breed around from the tailspin it was in during the early 90’s when I had them, thuogh it has been done before. The Portugese Water Dog is a shining example of what can be accomplished, and they started from a much smaller and even more genetically precarious base population.
I could tell you what happened to my two Ibizans, and my friend’s Ibizan, and all the horror stories I learned when I started calling around the country trying to find out what was happening to my hounds. I could tell you the gist of the conversation I had with the breed’s genetic research coordinator (a truly wonderful vet who really was doing his best to educate breeders and document what was happening) I could tell you the story of the courageous woman who wastaking “wobbler” puppies from dog show to dog show to educate and warn people about what they were not being told.
But if I told those tales, everyone reading this thread would start crying. Especially me. 
Moral of the story? “Rare” breed does not necessarily mean “healthier.”