In my experience the unhappy buyers are those with unrealistic expectations.
ETK - The first horse I vetted through RD, I was told the noise he made while u/s was not an issue, it had been vetted and was no problem, that no further workup was needed. After insisting (with a lot of pushback and cancellation of a test I was paying for), it turned out he had a collapsed airway that would not be treatable, along with a hard to treat infection of the airway. Prognosis was he would never be able to breath for any collected work.
The second horse I vetted and bought…when vetting we asked if she was ever injected, on sedatives, etc. Was told no, never…mare arrived in quarantine with a half used large bottle of sedatives with her name and dose instructions. It was a sedative that could only be obtained from a vet. She proceeded to nearly kill one of the handlers at a very highly experienced quarantine center…and was very dangerous to handle/ride at home. She also had multiple episodes severe colic (once while at the vet hospital for a behavioral eval)…the final one was so bad, we euthanized. Necropsy showed a rare acute on chronic pancreatitis…with high suspicion that she had been having episodes of pancreatits before I purchased her.
I don’t think my expectations were unrealistic.